Are all your accounts showing in tools > account settings?

It looks like all my Hotmail server ports , security and other settings have changed....Just from an update?? OMG. There needs to be a way to Go Back to the previous version after an update because this isn't the first time I have had trouble with an update of Thunderbird. I have donated to Thunderbird a few times and this is the thanks I get. I can use Outlook.com to read my email if I have to, but was very used to using Thunderbird. Thanks for the reply.

PS There is only one account in Thunderbird now, I forgot to answer that.

In my case, my Hotmail (Outlook with hotmail.com address) account seemed to automatically change from "Normal Password" to "OAuth2", and changing it back to "Normal password" made it start working again. I have another account that's an outlook.com and it wasn't changed.

I don't think personal email even supports OAuth, but perhaps the Thunderbird team thought because Microsoft is moving all school & business accounts there that they would be "helpful" and automatically move my account to OAuth, despite that it definitely is a personal account and not associated with an organisation.