I have one POP3 account (which is my primary account) and two gmail IMAP accounts set up in Mail.

The problem is that lately Mail has decided that for purposes of sending it defaults to one of my IMAP accounts. When I check Accounts > Account Information and look in the Outgoing Mail Server (SMTP) list, it lists my POP3 account and one of the other IMAP accounts as (Offline).

This is strange since none of the accounts are grayed out or have the sleep symbol next to them and under Mailbox they are all listed as being online.

Is there any way to force the two supposed "offline" accounts to become "online"? What has made them go "offline"?

Is there any way to designate one of these accounts as the default mail account?

Thanks for any help