The problem is as follows.
When you migrate user data from Thunderbird from one computer to another - all becomes wonderful, but POPs up the error window, type "Exceeded waiting for response from smtp.yandex.ru".
Demolished all. Put a naked Thunderberd and went loginit mail. 0 effect. Finds the appropriate configuration, and then writes that invalid username or password, or that cannot validate the configuration of the email account. Although using the browser - all perfectly goes.
In the browser settings of the mail account Yandex all permissions for mail programs exposed.
Tried everything provided by the Yandex settings for your email program.
There is a proxy. Play with the settings in Thunderbird have not changed anything.
Dug up all the settings. Exposed as on the other, normally operating computers in the network. Where Thunderbird is not megabiodiverse. The problem has not changed.
The problem with all mailboxes.
I think I'm going crazy. What is it?