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Thunderbird times out with smtp.outlook365.com

  • 2 replies
  • 1 has this problem
  • 34 views
  • Last reply by aldente-hu

Ben Kilminster
Ben Kilminster
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Hi,

I have what appears to be a common issue, but the common solutions I found don't seem to help.

I migrated to a new Mac[1], and my Thunderbird[2] on Mac times out while sending messages through the SMTP outlook server. So I am unable to send emails from account. By migrating, I mean I copied over my entire ~/Library/Thunderbird and used that. It actually did work for a few days. But then it started failing.

There are some common suggestions on the internet for how to fix this, and I have tried them all:

  • make sure correct settings are used. I am using Outgoing SMTP Server: smtp.office365.com, port: 587, security: STARTTLS, authentication: OAuth2.
  • make sure Firewall is disabled
  • restart Thunderbird
  • restart Mac
  • delete Thunderbird folder in Library, and just start over with a new profile.
  • change Thunderbird time out setting
  • check that I can send email from Mac Mail - yes, this works. It must a difference between Thunderbird and Mac Mail that causes the issue.

The error I get, after about 15 seconds is: "Send Message Error. Sending of the message failed. The message could not be sent because the connection to the Outgoing server (SMTP) smtp.office365.com timed out. Try again."

I have no problem receiving email, but am unable to send. 

I tried gomtp to look at what was happening, but I wasn't sure how to configure the ssl, tls, auth settings and how to specify where to find the password.

[1] Mac M4 Pro running Sequoia 15.3.1 [2] Thunderbird 137.0.1 (aarch 64)

Hi, I have what appears to be a common issue, but the common solutions I found don't seem to help. I migrated to a new Mac[1], and my Thunderbird[2] on Mac times out while sending messages through the SMTP outlook server. So I am unable to send emails from account. By migrating, I mean I copied over my entire ~/Library/Thunderbird and used that. It actually did work for a few days. But then it started failing. There are some common suggestions on the internet for how to fix this, and I have tried them all: * make sure correct settings are used. I am using Outgoing SMTP Server: smtp.office365.com, port: 587, security: STARTTLS, authentication: OAuth2. * make sure Firewall is disabled * restart Thunderbird * restart Mac * delete Thunderbird folder in Library, and just start over with a new profile. * change Thunderbird time out setting * check that I can send email from Mac Mail - yes, this works. It must a difference between Thunderbird and Mac Mail that causes the issue. The error I get, after about 15 seconds is: "Send Message Error. Sending of the message failed. The message could not be sent because the connection to the Outgoing server (SMTP) smtp.office365.com timed out. Try again." I have no problem receiving email, but am unable to send. I tried gomtp to look at what was happening, but I wasn't sure how to configure the ssl, tls, auth settings and how to specify where to find the password. [1] Mac M4 Pro running Sequoia 15.3.1 [2] Thunderbird 137.0.1 (aarch 64)

Modified by Ben Kilminster

All Replies (2)

Ben Kilminster
Ben Kilminster Question owner
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An update. I found one solution that worked but I don't know why, and I don't know if it solves the problem definitively or if it is something I need to do regularly. Perhaps this points to a deeper issue in Thunderbird?

Anyway, the solution ("solution 4" on https://www.nucleustechnologies.com/blog/fix-thunderbird-smtp-error/ is to 1) go to: Thunderbird -> Settings -> Privacy and Passwords 2) Then click on "Saved passwords", and delete the one(s) related to "smtp".

Immediately after doing this, I was able to send emails. (It did not ask me to re-enter the password.)

As I said, I don't know if this is a long-term fix. If you don't hear from me again, you can assume that it is.

Best, Ben

aldente-hu
aldente-hu
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I've met the same issue. If your Thunderbird was 128 before migrating and you can send mails from the same machine via another network (such as iPhone Personal Hotspot), switching the settings "security.tls.enable_kyber" false might resolve it.