I can receive and send messages.
Hallelujah!
What folders? ... Do you not see them under the HTTP account?
... they are user-created. I use my e-mail as a kind of filing system, I move my incoming mails into user-created storage folders.
OK. Re-reading this whole saga, it looks as if you might at some stage have removed the HTTP account (the one that wasn't working because of the authentication error) after following instructions to 'reconfigure' your account. Is this the case? If so, you
will have permanently deleted those folders and their contents, as a warning message will have told you when you removed the account.
If this is what happened, the only way to get those folders and their contents back on to your computer is to set up the account again, preferably to use DeltaSync but if you still can't get that to work, IMAP. Both of these will download all the account
folders from the server and keep them in sync.
I'm so sorry that you've been given this runaround. A lot of people have been experiencing this authentication failure (error 0x80048820 - Authentication Server Error) recently. A lot has been happening in respect of communications security, including Windows
Updates to some of the built-in systems and a general deprecation of SSL. I can't see that the support staff have done any troubleshooting to find out why this spate of errors has arisen, but I don't think it would take much to determine what the affected
users have in common. It might be something as simple as a Google-inspired disablement of SSL3. I have neither the time nor the facilities for conducting this sort of troubleshooting, and I think it's a poor show that the support staff don't care enough to
do it either.
Happy New Year!