Set-up guide
Connect Claude to email on your own domain.
Business email on your own domain, a mailbox your web host set up years ago, Fastmail, Zoho, GMX or Yahoo. If it speaks IMAP and SMTP, Claude or ChatGPT can work it with the address and password you already use, and the control panel looks up the server settings for you.
- Time About 3 minutes
- You will need 4 settings
- Encryption TLS on 993 and 465
The short version
Open the account settings in the mail client you already use, copy the incoming and outgoing server names, and paste them into the control panel with your username and password.
If you have a working mail client, you already have everything this needs.
Who it suits
Who this path is for
Use this if your mail isn't on Gmail or Microsoft 365. That covers more people than it sounds like.
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Any mailbox that speaks IMAP.
A mailbox that came with your web hosting, an independent provider such as Fastmail or Zoho, a mailbox your IT company set up on a server somewhere, or a domain you've had since before either of the big 2 mattered.
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On Gmail or Microsoft 365? Use their own guide.
The Gmail guide and the Microsoft 365 guide connect in ways that suit those providers better than plain IMAP does. For Microsoft 365, plain IMAP with a password isn't possible at all.
On screen
Watch an IMAP mailbox go in
The whole journey in 6 minutes, in real time with nothing cut: an account created, an IMAP mailbox added with its address, password and host, the connector pasted into Claude, and Claude answering its first questions.
In the video
- An account created at the control panel, with an email address and a password.
- An IMAP mailbox added: the address, its password and the host, tested before anything is stored.
- The connector copied from the mailbox's Connector tab and pasted into Claude under Settings, Connectors, Add custom connector.
- Two questions asked in Claude, answered from the mail in the mailbox.
The Claude half, step by step and with the reasons, is the Claude guide.
Before you start
The 4 IMAP settings, and how we find them for you
The same 4 any mail client asks for, which means you've supplied them before, even if you don't remember doing it.
- Incoming server (IMAP) imap.example.com : 993
- Outgoing server (SMTP) smtp.example.com : 465
- Username usually the full address
- Password or an app password
- Anything installed nothing
You may not need to look anything up. In the control panel, choose Any other email provider, type your address and press Find my settings. It checks the published settings for your provider, the public directory Thunderbird uses and your domain's own records, connects to what it finds, and fills in the servers.
It tells you where each answer came from, and says plainly when one is only a guess based on the domain.
Where to look
Where to find your IMAP settings if the lookup can't
The mail client you already use has all 4. It's the quickest place to look, and its settings are known to work.
In order of how quickly they give you an answer:
- The mail client you already use. Every desktop and phone mail app keeps these in account settings, and they're already known to be correct, which is more than can be said for a settings page written 5 years ago.
- Your provider's help pages. Search for the provider name and "IMAP settings". Providers keep these current, because every new customer needs them.
- Your hosting control panel. If the mailbox came with web hosting, cPanel and Plesk both have a "connect devices" or "mail client configuration" screen that prints the exact values.
What they usually look like
The shape is nearly always the same. Confirm the exact host names with your provider rather than assuming: the pattern below is a good guess, and a good guess is not the same as correct.
| Setting | Typical value | Notes |
|---|---|---|
| Incoming (IMAP) | imap.yourprovider.com, port 993 |
Implicit TLS. 143 with STARTTLS also works where the host upgrades the session; on a host that does not, 143 is plaintext. |
| Outgoing (SMTP) | smtp.yourprovider.com, port 465 |
Implicit TLS. Some providers use 587 with STARTTLS instead; both are fine. |
| Username | Your full email address | A few older hosts use a short system username instead. |
| Password | Your mailbox password | Some providers require an app password. Fastmail and iCloud both do. |
On hosting-provided mailboxes
If your mailbox came with your website hosting, the servers are often
mail.yourdomain.com rather than anything naming the host
company. That looks wrong, and it's usually right.
Walkthrough
Connect your own-domain email to Claude or ChatGPT, step by step
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Find your IMAP and SMTP settings
Collect the 4 values above. Copying them out of a mail client that's working now is the fastest route, and the least likely to go wrong.
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Add the mailbox in the control panel
Choose Add mailbox, then Any other email provider. Type your address and press Find my settings, then add your password. Where your provider offers a choice, use port 993 for IMAP and 465 for SMTP.
Use the TLS ports if your host offers them
TLS is supported, and it's what we'd rather you used. On 993 and 465 the session is encrypted before your password is sent.
It will also connect on a plaintext port if that's genuinely all your host offers. That's the right behaviour for an old internal server that would otherwise be unreachable, and it means your password and your mail cross the network in the clear.
Your settings decide, exactly as they do in any mail client. Use 993 and 465 unless your provider tells you otherwise.
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Add the connector to Claude or ChatGPT
In Claude: open Mailbox MCP in Claude's directory (or Customize, then Connectors, and search for it) and press Connect to Claude. Sign in to Mailbox MCP when it asks, and choose your mailbox.
Want one connector per mailbox, or no directory in your organisation? Add a custom connector: Customize, Connectors, + Add, Add custom connector. Give it a name, paste the connector URL from the mailbox's Connector tab in the control panel and press Continue, then Add without changing anything. Then press Connect and choose your mailbox. The Claude.ai set-up guide has every screen.
Claude starts a new connector's tools at Needs approval, so it asks before every step. We set ours to Always allow (open the connector under Customize, Connectors) and let the level you chose in the control panel be the limit.
In ChatGPT: select Plugins in the sidebar, find Mailbox MCP in the plugin directory, select Install plugin, then Continue to Mailbox MCP, and sign in. For a second mailbox, open the plugin again and press Connect another account. The ChatGPT set-up page covers developer mode too.
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Check the connection
Ask: Using Mailbox MCP, list my 5 most recent emails. If they're the messages you expect, the mailbox is connected, and nothing has been marked as read.
App passwords
Yahoo, iCloud and Fastmail want an app password
Some providers refuse your ordinary password from any mail program that isn't theirs. You make a separate password for apps in your account's security settings, once, and paste that instead. It's the commonest reason a correct password is refused.
- Yahoo Mail. Yahoo's steps: "sign in to the Yahoo Account Security page, click Create app password under 'External connections,' and follow the prompts". The lookup fills in the Yahoo servers for you.
- iCloud Mail. An app-specific password from account.apple.com, and a username trap worth knowing: connect Claude to iCloud Mail and your Apple calendar.
- Fastmail. An app password, made under Settings, Privacy & Security, with the Calendars and Contacts scopes ticked. The account password is refused.
Not supported
Providers this cannot work with
Worth knowing before you sign up rather than after, so here they are plainly.
Proton Mail
Proton Mail reaches IMAP only through Proton Mail Bridge, an application that runs on your own computer and decrypts your mail locally.
A remote server can't reach a bridge running on your laptop, so Mailbox MCP can't connect to Proton however correct the credentials are. That's Proton's design working exactly as intended, and it's a reasonable thing for them to have chosen.
Microsoft 365, over IMAP with a password
Not a Mailbox MCP limitation, and not something a setting can fix. Microsoft disabled Basic Authentication for IMAP on 1 October 2022, so no client can open those mailboxes with a password. Use the Microsoft 365 path, which takes one sign-in.
The same goes for a personal Outlook.com or Hotmail address: it connects with a Microsoft sign-in, once IMAP is switched on. Connect Outlook.com or Hotmail shows where the switch is.
Troubleshooting
If an IMAP mailbox won't connect
4 things IMAP hosts do differently, and the fix for each.
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Authentication fails, but the password is right.
2 usual causes. Your provider wants an app password rather than your account password, which Fastmail and iCloud both do.
Or your username is a short system name rather than your full email address, which some older hosting setups use.
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Mail reads, but sending fails.
IMAP and SMTP are separate services and can fail independently. Check the outgoing server name and port on their own.
A provider that uses 587 with STARTTLS rather than 465 is common and entirely fine.
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Folders have names you don't recognise.
IMAP hosts disagree about folder naming, and some prefix everything with
INBOX., so your sent mail isINBOX.Sent.Nothing is wrong. Ask for the folder by the name your mail client shows you.
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Sent mail isn't appearing where you expect.
On some IMAP hosts a folder exists but isn't subscribed, and mail clients that list only subscribed folders hide it.
Subscribing to the folder in your mail client makes it visible again, and breaks nothing.
The diary
An IMAP mailbox can have a full calendar too
One field connects it: the address of your host's calendar server. Not a second account with us, not a second connector in your AI client, not a second thing to pay for.
IMAP is a mail protocol, and there's no diary inside it. That's where most integrations stop, and it's why an assistant connected to an ordinary mailbox can read your week only by reading emails about it.
Most hosts run a calendar server alongside the mail one, speaking CalDAV, with an address of its own. Fastmail, iCloud, Nextcloud and StackMail all publish one, and so do most of the hosts that reach this page.
You paste the address and we open it while you wait. If it opens, the calendar tools appear on the connector you already set up. If it doesn't, nothing is stored, and you're told which of the address and the password was refused.
What your assistant can then do with the diary
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Read and search the diary.
Read the week and search it by subject, location or organiser. Open one event with everybody who was invited and how each of them answered.
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Find out who's free.
Ask when a group of people are free, and get back busy blocks rather than the contents of their diaries.
Somebody whose calendar can't be read comes back as unknown and never as free, which is the distinction that decides whether a meeting gets booked over their afternoon.
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Book your own time.
Book it, move it, repeat it weekly. A recurring meeting appears on every date it falls on, the way it does in Outlook, rather than once as a rule nobody can read.
Every time comes back in your calendar's own timezone, stated rather than assumed.
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Meet other people.
Invite people to a meeting, add an online meeting link, reschedule it and tell everybody, or cancel it with a message. Accept or decline an invitation that has come in.
What a CalDAV calendar can do is settled by asking it
CalDAV servers differ, genuinely and widely.
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Sending an invitation came later, and not everywhere.
RFC 4791 defines a store for calendar entries and says nothing at all about sending an invitation. RFC 6638 added that years later, and plenty of servers never followed.
A server without it will accept a meeting with people invited, answer that it worked, and tell nobody. That's the worst possible failure, because it's invisible from both ends.
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So we ask the server, the moment it connects.
Your assistant is handed only the tools the server actually answered for. A store-only calendar gets reading, searching and your own time; one that implements scheduling gets the meeting tools as well.
Nothing is offered that would then be refused, and the control panel shows you the list your particular server gave.
The CalDAV and CardDAV page has the addresses Fastmail, iCloud, Nextcloud, StackMail and Zoho publish, the app password each one wants, and the address book that usually lives on the same server. How AI calendar scheduling works, end to end, and what connecting a calendar involves, are each a page of their own.
Limits
What this connection does not do
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TLS follows your ports
Encryption follows the ports you enter rather than being forced. TLS is supported and preferred; use 993 and 465 wherever your host offers them.
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One mailbox each
One connection is one mailbox on one host.
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Connect the diary as well
IMAP is a mail protocol with no calendar inside it, so connecting the mailbox does not connect the diary. Most hosts run a calendar server alongside the mail one and it has its own address, which you give us separately. How the calendar connects.
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20 MB a message
Attachments are capped at 20 MB a message in total, not per file. A file already in your mailbox can use all of it; one the assistant writes itself is far smaller.
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A file the assistant writes itself
Only a file the assistant composes and has to write out itself is small. Files already in the mailbox, at a web address, uploaded through a one-off link, or in a ChatGPT conversation are streamed at send time and never pass through the model.
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Your host's send limits
Your host may impose its own send limits, and those still apply.
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Not a backup tool
It is not a backup, an archive or a migration tool.
Questions
Questions about IMAP email and AI
Can Claude read my IMAP email?
Yes. Connect the mailbox in the control panel with its address and password, add Mailbox MCP to Claude, and Claude can list, search and read it, and draft, send and file mail if you allow it. Reading doesn't mark anything as read. Any host that speaks IMAP and SMTP works, except Proton Mail, which only opens through an app on your own computer.
Can ChatGPT connect to an IMAP mailbox?
Yes, through Mailbox MCP. ChatGPT's own email apps cover Gmail and Outlook; this covers the rest. Connect the mailbox in the control panel, then install Mailbox MCP from the ChatGPT plugin directory and pick that mailbox when you sign in.
Do I have to find my IMAP settings myself?
Usually not. Type your address and press Find my settings: the control panel checks your provider's published settings, the public directory Thunderbird uses and your domain's records, connects to what it finds and fills in the servers. If nothing is found, the 4 settings are in any mail app that already reads the mailbox.
Why is my password refused when I know it's right?
Usually because your provider wants an app password rather than your account password. Yahoo, iCloud and Fastmail all do. Less often, an older host wants a short username instead of your full address.
Can I connect Proton Mail?
No. Proton Mail opens over IMAP only through Proton Mail Bridge, an app on your own computer, and a server on the internet can't reach it. That's Proton's design working as intended.
Does it work with email from my web hosting, such as cPanel or Plesk?
Yes, and those are what this path was built for. The servers are often mail.yourdomain.com, which looks wrong and is usually right. If the settings lookup can only guess them, it tells you it guessed.
Attribution
Sources
- Proton Mail Bridge Why Proton mailboxes are reachable only from the machine running Bridge.
- Fastmail: server names and ports An example of a provider that issues app passwords for mail clients.
- RFC 8314: cleartext considered obsolete The standard that makes implicit TLS on 993 and 465 the recommended way to reach a mailbox, which is why this page asks for those ports.
- Yahoo Help: generate and manage third-party app passwords Where a Yahoo app password is made, quoted above. Read 4 October 2026.
Connect an IMAP mailbox.
The free tier is 5 calls a day on any mailbox, which is enough to find out whether your host behaves the way this page expects before you pay anything.