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

My microsoft account is signed in with a @yahoo address.

yesterday my pc outlook was working fine, with both my microsoft account signed in, and my third party email service.

now i restarted my pc, got an update, and boom, not i can't SIGN MY **** MICROSOFT ACCOUNT IN. because, if i use the @yahoo account, which has been my microsoft sign in for over 15 YEARS, it signed in the damn yahoo account only. why the hell is is so difficult to sign into my freaking outlook/microsoft account?

i tried swapping to an alias, and that didn't work either.

Im trying to set up an outlook account so I can access my emails. it asks me to add a new email address. i don't have a new email address cant i use my old one do i create a new one

Ok, so working with support, here's what worked for me.

Delete all mailboxes from new outlook
Change Microsoft account alias from custom @xyz.com back to default @outlook.com

(I had to walk away and at least 12 hours passed - no idea if that was needed, just putting it out there in case you try right away and it fails)

Launch new outlook

Add Microsoft @outlook.com mailbox

Add @xyz.com mailbox (for me this was IMAP)

Change Microsoft account alias from default @outlook.com back to custom @xyz.com

I have no idea how to do what you suggested which is to "Delete all mailboxes from new outlook
Change Microsoft account alias from custom @xyz.com back to default @outlook.com".

Would you be able to explain how to do this? Thanks.

Great, thank you for these details. My email is a gmail, would it work with a different email than an Outlok email.

It been 2 weeks... pretty frustrated with Microsoft updates :(