Thunderbird 13 won't download email

[vova82]

Hello I just installed TB13 and set up Yahoo and AOL mail accounts and at first it worked all fine.But now when I try to download mails it does nothing,even if there on the servers are new mail waiting.Please help.

UserAgent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:12.0) Gecko/20100101 Firefox/12.0

[Fulvio]

How did you set up the two accounts. Have you tried to download mail, manually,? i.e. hitting Get Msgs button?
I have, just, checked my Mail, and the two accounts are only some of the many which I have. They are set up as imap accounts, and Yahoo has rarely failed to work. When it failed I got a server error. But this morning it worked. As usual, one good mail, three directly to Trash, as directed for Spam, and four stubborn ones in the Bulk mail folder. I get very little mail from AOL.

UserAgent: Mozilla/5.0 (Windows NT 5.1; rv:13.0) Gecko/20120604 Firefox/13.0 SeaMonkey/2.10