I emailed support yesterday but haven't heard back.

I've tried adding and disabling two-factor. I've tried adding and removing an App Specific Password, logging in at each stage.

I followed the credentials precisely in your Thunderbird Guide. After adding my email address, Thunderbird retrieved all the settings from the server, which precisely matched your sample screenshots.

For imap server, I tried imap, and imappro.zoho.com

It just continues to say "Unable to login at server, probably wrong configuration or password.

I know that my password is correct because I used it to login to the ZohoMail Android App