No one can assist without knowing the complete error message you are seeing and also having a screenshot of your SMTP server settings pane. Provide those, and someone may have suggestions. thank you.

Thanks for you reply. I'm enclosing images. The error message says: The mail could not be sent because ther time for the connection to the SMYP-server ran out.

OK, it looks good to me, but there are others with strong teckie knowledge. I will try to locate one.

Any news, David?

I have sent inquiries, but there are only so many volunteers. I will check later.

Timeout issues are always a mess. Many are directly caused by antivirus software. It takes them so long to do nothing useful that the server just gives up and drops the connection.

So, if stopping any outgoing email scanning does not stop the rot, about the only way to get to the bottom of this sending issue is to actually log the connection to the server and see exactly what is taking to the time to result in a timeout.

So to that end. use the Config Editor to change the hidden preference mailnews.smtp.loglevel, set it to All

Now when you are ready to send your email open the error console. (Ctrl+Shift+J) and use the clear/trash button to remove everything that is shown there already.

Now click send Review the messages that appear in the console immediately before the time out. Note you can right click in the console and select copy all and then go to pastebin and make a paste of the log that David and I can look at after you post a link to the paste.

Extra note: You can manage the paste if you have an account with pastebin and are logged in. Anonymous pastes stay available forever basically for anyone with the link.

If the error are about reading a file or sending the file to the server look for antivirus issues, either scanning in the temp folder or scanning the outgoing mail (it is truly amazing how repetitive this software is looking for something it has already said it can not find (it certifies nothing found when it scans your system) but write the email to the temp file ready to send. It scans. convert any binary attachment to mime as must happen and it scans it again in memory write the modified content to temp and it scans it again send the file to the server and you guessed it, another scan.

"Insanity is doing the same thing over and over and expecting a different result." is attributed to many sources but possibly belongs to Narcotics Anonymous. That does not exclude the similarity of the actions being taken by antivirus products. Personally I think the repetition is insane. Oddly enough I am not a fan of email scanning, either incoming or outgoing because incoming with Thunderbird the risks are almost non existent and outgoing you can't find what you do not know about.

I have sent inquiries, but there are only so many volunteers. I will check later.

Sorry, but I have been pretending to be a carpenter in my spare time of late. That is the sort of thing that happens when you live in a house that is falling down ;). So support has largely dropped off my list of things I have time for. Perhaps I should retire like the wife has, but where is the fun in that. Rather be run off my feet really.