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Mac OS Monterey update results in failed sends

Louis de Beaumont
Louis de Beaumont
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Hi, thanks for all your help.

I updated to Mac OS Monterey this evening, and since the update haven't been able to send emails. Receiving emails works fine.

Using gmail server smtp.gmail.com Port: 465 Auth. method: OAuth2 Connection Security: SSL/TLS

I've followed every bit of advice I could find:

  • Setting SMTP auth to normal password (from OAuth2)
  • Deleting saved passwords and reauthenticating with Google, repermitting Thunderbird etc.
  • Turning OS firewall off and trying to send (same 'unknown error' thrown)
  • Reinstalling Thunderbird
  • Setting auth to 'No authentication' fails because Google (and I) require it

I'm assuming it's to do with my OS update, but I could be wrong. Any advice?

Hi, thanks for all your help. I updated to Mac OS Monterey this evening, and since the update haven't been able to send emails. Receiving emails works fine. Using gmail server smtp.gmail.com Port: 465 Auth. method: OAuth2 Connection Security: SSL/TLS I've followed every bit of advice I could find: * Setting SMTP auth to normal password (from OAuth2) * Deleting saved passwords and reauthenticating with Google, repermitting Thunderbird etc. * Turning OS firewall off and trying to send (same 'unknown error' thrown) * Reinstalling Thunderbird * Setting auth to 'No authentication' fails because Google (and I) require it I'm assuming it's to do with my OS update, but I could be wrong. Any advice?

Chosen solution

I have solved the problem. Funny how posting on support boards is part of getting closer to the solution, even if not providing the answer.

My issue was the attached file I was trying to send. Google was flagging it as a security threat; the file was from an old family computer and needed updating (i.e. saving with a modern program).

Possibly Thunderbird would like to note this error message and pass it from Google back thru Thunderbird. (Not to be presumptuous. Great app. Long live Mozilla. Thanks.)

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All Replies (2)

Louis de Beaumont
Louis de Beaumont Question owner
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Also my draft email has synced with the Google servers (i.e. I can see it on mail.google.com), and I can send emails using mail.google.com in browser.

Louis de Beaumont
Louis de Beaumont Question owner
more options

Chosen Solution

I have solved the problem. Funny how posting on support boards is part of getting closer to the solution, even if not providing the answer.

My issue was the attached file I was trying to send. Google was flagging it as a security threat; the file was from an old family computer and needed updating (i.e. saving with a modern program).

Possibly Thunderbird would like to note this error message and pass it from Google back thru Thunderbird. (Not to be presumptuous. Great app. Long live Mozilla. Thanks.)