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

I'm having the exact same issue. I just made my new outlook.com email my primary alias for my Microsoft account. My previous primary alias was a gmail.com email. I was trying to experiment and see if I could get Microsoft To-Do integration if I signed in to New Outlook with the Microsoft account I was using for To-Do. But I had to change my primary alias to avoid Outlook confusing my Gmail account with my Microsoft account. But when I tried to sign in, I had the same issue as OP.

Hello ShadeZinc,

Where's that switch?

Hello,

I’m sorry to hear that you’re still having trouble adding your email account to Outlook. Checking your Microsoft credentials is a good idea. Let me know if there’s anything else I can do for you.

Kind Regards, Segunfunmi

I have a similar issue. When I add an Outlook.com account, it adds correctly. However, it does not show in my accounts list. When I try to add it again, it says that account already exists. I just need it to show in the acccounts list.

I finally got on with Microsoft outlook help. They offered to toggle back to the old email format for me.

I then added all 3 email accounts. Everything now works. I will not toggle back to the new email because I think it is junk.

They may force me someday but I will cross that bridge when I come to it.

Thanks for your help.