You are aware I assume that the from address has no bearing on if mail is considered junk except for it's use in the whitelisting of senders.

See https://support.mozilla.org/en-US/kb/thunderbird-and-junk-spam-messages#w_whitelisting

Thank you, Matt, for the response. I've read the article on TBird junk and I admit that I don't completely understand how the app decides what is junk. For context, I've used TBird for many years and recently had to remove and reinstall it because of an issue with my server. I had no issues prior to that. I have adjusted the settings per the article and have marked all messages as either "junk" or "not junk" on a daily basis for the past week or so, which is my understanding of the "whitelisting" procedure. All of that has had absolutely no effect on the massive amount of junk mail that comes in on a daily basis. Same senders, same subjects, in most cases several times a day. If my constant deliberate marking messages as junk and not junk is not among the criteria that the algorithm takes into account, then I'm obviously missing something. I'm sure I'll be embarrassed when I find out what it is. If you can point me in the right direction I'd be grateful.