I have a friend and business client with whom I've been emailing for thirty years. About six months ago, his emails to me began to be automatically placed in the "junk" folder. They weren't even showing up in my Inbox with the "looks like junk" icon. Thunderbird claims to "learn" and "unlearn" what email is tagged as junk, but in this case, the sender was NEVER tagged as junk. Furthermore, I have been constantly retrieving their emails from the Junk folder and identifying them as "not junk" by selecting the email and pressing shift+J. Yet they are still automatically getting dumped in the junk folder. Can I possibly override Thunderbird's mislabeling of this email address?