New Outlook won't let me add my outlook email account.

I had the same issue adding an M365 account. I have two accounts and one worked and the other didn't. Did the following and it solved the isssue:

• Close the new Outlook app.
• Click the Start menu and search for 'Command Prompt' > Right click the app and select 'Run as Administrator'.
• Now, please copy/paste the following command and hit the Enter key.

olk.exe --clearLocalState

This worked for me.

Cause: My Mircosoft Live account had my Gmail account set as it's primary alias. Plus, I had already set up my Gmail account in the New Outlook. When I tried adding my Outlook email account, it was trying to add a Gmail address to New Outlook which already contained a Gmail address.

Solution: Log in to Microsoft at account.microsoft.com/profile and under the heading"Account info" click on "Edit Account Info". Then next to your outlook.com address click on "make primary". If you return to New Outlook and try to add your outlook email address, it should now work.

Thanks for your help - problem solved.

I have a btinternet.com mail account and New Outlook now displays my mail, contacts and events. So simple why do Microsoft not suggest this solution.

This worked for me.

Cause: My Mircosoft Live account had my Gmail account set as it's primary alias. Plus, I had already set up my Gmail account in the New Outlook. When I tried adding my Outlook email account, it was trying to add a Gmail address to New Outlook which already contained a Gmail address.

Solution: Log in to Microsoft at account.microsoft.com/profile and under the heading"Account info" click on "Edit Account Info". Then next to your outlook.com address click on "make primary". If you return to New Outlook and try to add your outlook email address, it should now work.

I quit trying to make Outlook work with so many issues, and I am now using the Yahoo email app, which allowed me to add accounts from Hotmail, Gmail, apart from their own Yahoo, in a breeze. I wish Microsoft easied things up, not complicated them, because I don't have time or attention to deal with them.