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quib21
User level: Level 1 (4 points)

Apple Mail on MacBook Air uses incorrect signature and SMTP server for Gmail

Dear Apple Support Team,

I am requesting technical assistance with an issue affecting Apple Mail on my MacBook Air (2020, Intel Core i3), running macOS Sequoia 15.8.2.

I have two email accounts configured in Apple Mail:

  • Gmail: *** – personal account, using the signature “Gmail prywatny”.
  • iCloud: *** – business account, using the signature “służbowy”.

Problem description

When composing a new message from my Gmail account, Apple Mail displays the correct Gmail sender address but automatically inserts the business signature associated with my iCloud account.

In some cases, the signature selection menu offers only the iCloud business signature, even though the personal signature is correctly assigned to Gmail.

I have also encountered an outgoing mail issue. Apple Mail attempted to send a message from my Gmail address through the iCloud SMTP server (smtp.mail.me.com). The server rejected the message with the error: “From address is not one of your addresses”.

Troubleshooting already performed

  1. Verified signature assignments and default signatures for both accounts.
  2. Checked email account and outgoing SMTP server configurations.
  3. Tested both automatic and manually selected default sending accounts.
  4. Tested Apple Mail in macOS Safe Mode, where the issue persisted.
  5. Created a separate macOS user account and tested Gmail signatures successfully.
  6. Backed up and attempted to regenerate signature configuration files, including AccountsMap.plist, without achieving a permanent fix.

Interestingly, when replying to messages received through Gmail, the correct personal signature is available. The issue primarily affects newly composed messages.

This suggests a problem specific to the Apple Mail configuration within my primary macOS user profile.

I would appreciate escalation to the appropriate Apple Mail technical support team and guidance on restoring correct account, signature, and SMTP server associations without having to create a new macOS user profile.

I can provide screenshots of the error and additional diagnostic information upon request.

Kind regards,

Maciej ***


[Edited by Moderator]

Posted on Nov 2, 2026 3:41 PM

2 replies

kaz-k
User level: Level 9 (53,902 points)

Nov 2, 2026 6:26 PM in response to quib21

Hi,

To fix an incorrect outgoing SMTP server and signature for Gmail in Apple Mail on your MacBook Air, you need to manually update your account settings in the Mail app preferences.

Fixing the SMTP Server

  1. Open the Mail app on your Mac.
  2. Click Mail in the top menu bar, then choose Settings (or Preferences).
  3. Click the Accounts tab, then select your Gmail account from the sidebar.
  4. Click Server Settings next to Account Information.
  5. Uncheck Automatically manage connection settings if it is selected.
  6. Locate the Outgoing Mail Server (SMTP) pop-up menu and select Edit SMTP Server List.
  7. Ensure the server name is set to smtp.gmail.com.
  8. Set the port to 587 (with TLS) or 465 (with SSL) and verify your full Gmail address is entered under authentication.
  9. Click OK, then save your changes.

Fixing the Incorrect Signature

  1. Open Mail > Settings (or Preferences).
  2. Click the Signatures tab at the top.
  3. Select your Gmail account from the left-hand list.
  4. Drag the correct signature you want to use into your Gmail account, or create a new signature specifically for that account.
  5. In the Choose Signature drop-down menu under your Gmail account, select the correct signature so it applies automatically.


Burgunde
User level: Level 1 (38 points)

Nov 5, 2026 4:18 PM in response to quib21

Since it works in a new macOS user, your account's Mail data is the problem, not Gmail. A fix to AccountsMap.plist often doesn't last because iCloud puts its own copy back, so stop that first.


1. Quit Mail.

2. System Settings > your name > iCloud > iCloud Drive > Apps syncing to iCloud Drive: switch Mail off.

3. Copy your home folder > Library > Mail > V10 > MailData > Signatures somewhere safe, then move AccountsMap.plist out of that folder.

4. Open Mail > Settings > Signatures. Drag "Gmail prywatny" onto the Gmail account and pick it under Choose Signature.

5. Settings > Accounts > Gmail > Server Settings: set Outgoing Mail Account to the Gmail one, not iCloud.

6. Test a new message, then switch Mail back on in iCloud Drive and check it holds. If it flips back, the iCloud copy is the bad one, so leave Mail off there.


More on signatures per account: https://autographs.app/guides/apple-mail-signature-per-account/

Originally posted at discussions.apple.com/thread/256387809