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SMTP port 587 STARTTLS

markus.grassl
markus.grassl
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Hello,

After the automatic update of Thunderbird Destkop (Windows 10) to version 1.140.0 and then a manual update to 141.0, I cannot send emails using port 587 with STARTTLS (e.g., for an account hosted at smtp.office365.com).

Sending mail from other accounts via port 465 using SSL/TLS still works. Also, using an older version for Linux with the same setting for port 587 works.


Does anyone else experience a similar problem? Has there been a change in the implementation of STARTTLS?


Markus

Hello, After the automatic update of Thunderbird Destkop (Windows 10) to version 1.140.0 and then a manual update to 141.0, I cannot send emails using port 587 with STARTTLS (e.g., for an account hosted at smtp.office365.com). Sending mail from other accounts via port 465 using SSL/TLS still works. Also, using an older version for Linux with the same setting for port 587 works. Does anyone else experience a similar problem? Has there been a change in the implementation of STARTTLS? Markus

Chosen solution

Thanks. My settings are all correct (and unchanged). It turns out that there was a coincidence of the update and an incorrect change of the network settings. The latter blocked port 587. Using VPN, the problem doesn't show up. Sorry for the false alarm.

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All Replies (2)

sfhowes
sfhowes
  • Top 10 Contributor
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STARTTLS on 587 is correct for smtp.office365.com. Is the authentication method set to OAuth2?

Helpful?

markus.grassl
markus.grassl Question owner
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Chosen Solution

Thanks. My settings are all correct (and unchanged). It turns out that there was a coincidence of the update and an incorrect change of the network settings. The latter blocked port 587. Using VPN, the problem doesn't show up. Sorry for the false alarm.

Helpful?

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