Can't connect to server / Authentication error
I have 3 different hotmail accounts. And tried to set them up in a newly installed thunderbird app on windows (10,sorry not up to date). In the beginning I had 2 out of 3 working, but the last one is my business account and it didn't connect. I tried many different ways to get it working, and now only the 1st one is still connecting correctly. The second one also doesn't connect anymore and is giving me the: "The connection was refused when attempting to contact localhost." or Authentication error: Unable to log in at server. Probably wrong configuration, username or password.
I know for sure password and username are correct. I have added thunderbird to exceptions in firewall. I also tried turning the firewall off. no changes. I have no idea where it got so messy but can someone guide me in this? Most of it I do not understand so it is obvious I made mistakes.