I have 4 accounts on TBird. 3 are personal and one is work. My work account gets the bulk of the traffic. Last week emails sent from this account stopped being received by people that I had sent them to. I used a backup profile that I had on another computer and replaced it on my desktop. That worked, but I lost 11 days of emails. I thought the issue was fixed. Today it has started again. Any mail sent from the other 3 are getting to their destination. I had 16k messages in my sent folder so I archived 10k from last year and I also archived my received messages from last year. I was hoping that would fix the problem but it did not.

Help!