I am getting the message:  cannot send or receive email from this account.  It doesn't seem to be recognizing the Incoming Mail Server POP3, because a different Mail Server is now listed instead, and it's listing a message that I wrote some time back in answer to another kind of problem.  That message is now listed next to my Server, instead of POP3.  Anyway, it's no longer recognizing Server.  How do I correct it?