I'm very confused. I've been using Thunderbird as my email server for a few years. Recently, I stopped receiving emails December 12, 2023. I sent in a problem according to the help page that I found. I believe Mozilla is now the server for Thunderbird? I don't even know if that is accurate (part of my confusion). I followed prompts and confirmed my email address, apparently I now have a user name. I still can't send or receive emails. Can you help. I need step-by-step instructions, please.