Password
Every so often, when I log into Thunderbird, it will ask for my *password*. I have checked it so that it remembers my password, but once in a blue moon, it will ask me for my password. Why does this keep happening?
Opaite Mbohovái (1)
Your email provider may have restrictions on the number of simultaneous email connections to cache. GMail enforces such restrictions, among other providers. This is generally done to prevent abuse and for security reasons.
The default in Thunderbird is 5. Try changing it to a lower number.
This setting can be found under Tools > Account Settings -> Server Settings -> Advanced -> IMAP -> Maximum number of server connections to cache.