I use Thunderbird to manage three email addresses. One is a gmail account that is set up using IMAP. The other two are attached to my own domains and are set up using POP. I began having problems today. The two POP accounts no longer send or receive messages. The gmail/IMAP account is receiving but it will not send. When I try to send a message I get the following error messages:
Gmail/IMAP account: "Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) smtp.gmail.com was lost in the middle of the transaction. Try again."
POP account 1: "Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) secure.emailsrvr.com was lost in the middle of the transaction. Try again."
POP account 2: "Sending of the message failed.