SMTP timeout error - 4.4.2 TB52.4.0

[tanstaafl]

You could install a older copy of Thunderbird in a different directory (using custom setup) . It will use the same profile, and you could switch between the two versions as needed to see if it makes a difference which one you use. See http://kb.mozillazine.org/Go_back_to_an ... hunderbird

"I am using Windowws Defender, and I do not think it scans email"
Just double checking, no separate AV software such as Avast!, Avira, AVG, McAfee, Norton etc.? The windows defender security center (just type security in the Start search field and it should suggest that app) has a anti-virus icon that if you double click on it tells you what AV you are using.