MacOS Monterey Mail app, BT mailbox error message

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Level 1

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MacOS Monterey Mail app, BT mailbox error message

I have 2 mailboxes in MacOS Monterey (12.4) Mail…@icloud.com (working fine) and …@btinternet.com (some errors).

My BT mailbox works fine if the originator is in my Contacts, or from my wife’s BT email. Both our BT emails share the same BT account.

However, emails from 3rd parties not in my Contacts prompt the following error message. “Mail was unable to open this mailbox on the server ??. The server returned the error: Mailbox does not exist”. After clicking OK on the error the email appears correctly in my BT mailbox; ostensibly nothing wrong!

Both Mac Mail preference and online BT account settings are correct; corroborated by the fact that some BT emails are landing correctly! The error message is more of an irritant than anything else, but how can I stop it?

Mac mini, macOS 12.4

Posted on Jun 6, 2022 11:48 AM

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Answer 1

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leroydouglas

Community+ 2024

Level 10

188,532 points

Jun 6, 2022 12:50 PM in response to Salmon4you

Salmon4you wrote:

I have 2 mailboxes in MacOS Monterey (12.4) Mail…@icloud.com (working fine) and …@btinternet.com (some errors).

My BT mailbox works fine if the originator is in my Contacts, or from my wife’s BT email. Both our BT emails share the same BT account.

However, emails from 3rd parties not in my Contacts prompt the following error message. “Mail was unable to open this mailbox on the server ??. The server returned the error: Mailbox does not exist”. After clicking OK on the error the email appears correctly in my BT mailbox; ostensibly nothing wrong!

Both Mac Mail preference and online BT account settings are correct; corroborated by the fact that some BT emails are landing correctly! The error message is more of an irritant than anything else, but how can I stop it?

Mail issues loading content in macOS Monterey...

Open mail app select Mail>Preferences>Privacy disable all and compare your results:

• “Protect Mail Activity” /

• “Hide IP address” /

• “Block all remote content”

Use Mail Privacy Protection on Mac - Apple Support

If it resolves your issue, you can enable one at a time to isolate the problem feature or leave them off.

Not all mail servers are going to play nice...

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Answer 2

Salmon4you Author

Level 1

4 points

Jun 10, 2022 4:34 AM in response to Salmon4you

I thought the problem was resolved when an email went into my BT junk folder without an error message, but not so. Error messages have popped up on 2 further BT emails from 3rd parties, not in my Contacts. After clicking OK on the errors, both landed successfully in my BT inbox.

“Mail Privacy Protection” is unticked in my settings and between receipt of these last 2 emails I rebooted my Mac to make sure the setting change had taken effect.

Do you have any other thoughts on what is causing this error: “Mail was unable to open this mailbox on the server ??. The server returned the error: Mailbox does not exist”

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Answer 3

Salmon4you Author

Level 1

4 points

Jun 12, 2022 4:19 AM in response to leroydouglas

I thought the problem was resolved when an email went into my BT junk folder without an error message, but not so. Error messages have popped up on 2 further BT emails from 3rd parties, not in my Contacts. After clicking OK on the errors, both landed successfully in my BT inbox.

“Mail Privacy Protection” is unticked in my settings and between receipt of these last 2 emails I rebooted my Mac to make sure the setting change had taken effect.

Do you have any other thoughts on what is causing this error: “Mail was unable to open this mailbox on the server ??. The server returned the error: Mailbox does not exist”

Reply

Answer 4

Salmon4you Author

Level 1

4 points

Jun 9, 2022 1:14 AM in response to leroydouglas

Problem resolved by turning off the mail privacy settings. Thank you for your help

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MacOS Monterey Mail app, BT mailbox error message

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