feliperijo said

It's all in the question. The account is on SMTP, and this never happened until today.

It is all in the subject I think.

That sounds like an anti virus issue. It is having a nap and needs time to wake up. Try disabling anti virus scanning of mail and see how you go.

(i'm running Windows 7)

No anti virus running here, just Spybot 2 and Trusteer Rapport for banking websites, but I think none of these monitor SMTP ports.

More importantly, everything was fine until yesterday after the update. No issues with TB in the previous 2 years.

I must have been asleep yesterday. Errors with the decimal points like 4.7.1 are issues by the mail server, not Thunderbird. Thunderbird just passes them through. So whatever the issue, it is at the server end, not the Thunderbird end. What does your mail provider have to say?

Hi Matt!

Unfortunately our service provider is one of those 'behemoths' that couldn't care less, specially because the system is working, after all. It just takes two consecutive 'sends' for it to work.

It just strikes me as odd that this behavior started after the update. Perhaps there was a change in the way the message is sent, to make it quicker.. or.. something?

Thanks a lot!