The emails probably were out of order because you sorted them on some other column besides the Date column. You can tell what column is being sorted by the small pointer in the header. Click the header labeled DATE to sort by date. Click DATE a second time if you need to reverse the sort. I cannot begin to guess why you are not downloading messages from your providers server. So far all you have said is that it is broke. How a about a few details of what is or is not happening or any error messages. Go to your providers webmail site and see if you have any new messages there. Thunderbird downloads them from your providers server and if there is nothing there Thu service cannot fix that.

The out of order is not a problem. I mentioned it because I thought it might give a clue as to why my emails suddenly stopped.

I did not say it is broke. I said emails suddenly stopped being posted. There were no error messages. I generally get hundreds of emails from one source to this email address. I have checked with that source and they assure me they are sending emails as they always have. There are no indications from my provider that there are email problems. I find it strangely coincidental that Thunderbird instituted a new email program on or about the day me emails stopped being posted. Should I simply open a new email with a different browser?

What do you see when you go to your providers web mail page? Do you have messages there?