lease send a screenshot of the error message you are receiving.

Hi, thank you for your reply. I will as soon as it happens.

Please see the attached PIC. The SERVER is fine and after I rebooted the PC, I could send the Mail.

Please see the attached PIC. The SERVER is fine and after I rebooted the PC, I could send the Mail.

Timing out on an SMTP server is indicative of a problem with Third Party Anti-Virus software - especially Bitdefender.

If you search for the string "the connection to the outgoing server SMTP timed out" in the top right search field, there will be numerous articles with information about how to resolve this issue.

The most common solution is that Anti-Virus software needs to be switched off from scanning emails.

If the solutions offered don't work, please reply to the post and it will be relisted as in need of a solution.

A 'test' is to start Windows in Safe Mode with Networking to see if the problem persists but it does appear from your post that the occurrence is intermittent.

Hi, I use ESET ENDPOINT ANTIVIRUS. The next time it happens I can either suspend ESET's protection (which is generic) or ESET's Mail Client protection (which is specific). I'll report back. Thank you.

Hi, I use ESET ENDPOINT ANTIVIRUS. The next time it happens I can either suspend ESET's protection (which is generic) or ESET's Mail Client protection (which is specific). I'll report back. Thank you.

There are a lot of people who come on the Forum with the same sort of problem. They have decided against using the free, inbuilt Windows Security Suite in Windows and opt for Third Party Anti-Virus Software - which then causes a raft of error messages that aren't obvious are being caused by it.

I have never seen a problem with the Windows Security Suite. At least, not yet. Unfortunately, I can only point you to the likely solution - I have no experience of altering Third Party AV to allow TB to do its job.

Hope the solution works.

Hi, it happened again. So, I suspended ESET's protection (which is generic) but that didn't help. After the reboot I could send the Mail. I'll remove ESET and see if it happens again in the next days.

The error message is a timeout, so Thunderbird is sending the co0pnnection request and somewhere in there is is timing out. About the only way to get an idea is logging.

Use the Config Editor to change the setting mailnews.smtp.loglevel, string, set to All

Next time the issue occurs open the error console. (ctrl+Shift+J) Right click over the messages and select copy all messages to a file.

Once you have the file post here and can work out what to do with it based on how large it is. (posting to this forum is not a good idea at all.)