A few years ago, United started requiring MileagePlus members to login to their accounts using an alphanumeric username (rather than an email address) and password. I've been doing that, as recently as 9/26.

Today, I tried to login to my MileagePlus account on United.com, using that alphanumeric username, and got this response: "Please enter only letters A-Z or numbers 1-9." Now, there's a long MP account number associated with the alphanumeric username I've been using, so I entered that instead, along with the same password. It worked.

However, the same procedure does NOT work with the United app on iPhone--it still requires the older alphanumeric MP member username.

I've seen no announcement on the United website of any procedure change--and given that United is trumpeting a big deal about using the United app for contactless login at airports during the pandemic, you'd think they'd being trying to get this in order.

Has anyone come across this problem, or have more information?