First Are you connected to the internet using spectrum? Required to send mail at least.

Have you tried without your anti virus running? Try using just defender. I have found that many antivirus products, especially those with firewall components cause new account creation to simply fail. The worst in my experience for that being Norton. Their Sonar feature turns the new account wizard into an automatic fail.

Yes I am. I’ve been “forced to install Outlook 2010. And sadly, It works perfectly. With a simple imap configuration. So does apple email to my iPad and iPhone. I’ve temporarily saved my entire 2000 Tbird emails to an external drive . I’ve been doing that every 2 months. For the past 3 years. Yes I have tried disabling Avast premium antivirus for up to an hour. At least 10 of the failed reinstalls. I don’t much like Outlook. Too bloated I will try to not give up trying to reinstall Tbird. But it’s inexcusable that I can’t acquire a clean install. I retain every version of Tbird that has existed for 2O years from their own website. Up until about 2 years ago . If I preferred an older version of Tbird. I could and did roll back to a previous version. 2 years ago they stopped allowing you to do that. And began to warn . That if you attempted it they wouldn’t take responsibility if you lost your data (Emails) folders . This is very sad. This should not be happening. I could delete Outlook and reinstall any version I want to.There are at least 5 since 2007. Not Tbird. Open source has its drawbacks. No one at Tbird will take responsibility for the program. All their community resources care about is that any questions or comments are Not “ offensive.” What do they think happens to someone’s frustration level when they confront a problem like I’m having . I prefer a standalone email program that works. For years there are only 2 good ones. Outlook and Tbird. All the rest are web based. And even Outlook has sorta switched to a web based client called Microsoft 365. On subscription only. Thanks for trying.