Thunderbird uses what you entered in Account Settings for that account.

Right click the account in the Folder Pane on the Left side and select Settings. Click Server Settings and read the server name there. Edit it if you need to.

I will either have to find the incorrect server name and delete it or delete the account on TB and create it again. It is my understanding that deleting the account on TB will also delete all the emails and/or folders too.

What was the server name for the account when you followed the above instructions?

What makes you think the server name is wrong?

Personally I do not know what you think you are going to gain by deleting the account. Server names are very easy to edit. But go ahead. It will solve nothing but it will keep you busy for a while.

Move emails to folders under the LOCAL FOLDERS account before deleting any account.

Being unkind isn't necessary and you don't seem to be familiar with Thunderbird. The server name is correct in the settings so, no, it doesn't use what is in the settings but uses an incorrect name. The server technicians are unable to solve this issue and suggested deleting the account. It is obvious it is incorrect because messages don't download and shows incorrectly in Password Manager, so this isn't difficult to figure out. The new replacement account should use the auto configuration and pick the correct server just as it did when I created the subaccount. But deleting the account is my last resort!

I does use that name. It does not make one up. You are probably right. I have just been working this forum answering questions for over 4 years now so I do not know squat. I will let your knowledgeable server tech and you figure this one out. You seem to know it all.