We were unable to sign in to review your app with the demo account information you provided - But it works on our Testflight

Hello,

I've submitted our new App to App Store Connect, and receive the following error message from Apple: "We were unable to sign in to review your app with the demo account information you provided."

I've got the exact same version of the App on my (real) iPhone and can login with the same Credentials without a problem. The debug information from the Screenshot Apple provides that it didn't even connect to our server - so the login wasn't recognized as false but the app couldn't connect to the server.

We're using normal Authentication (using a Authentication header and https). Could there be a reason why Apple can't connect to our server but all testers can?
I'm having the same issue. Our app has been on the store for a couple years and now the reviewers can't log in on my most recent update I submitted a few weeks ago. I'm able to sign in with the demo account on a number of different devices but when I asked for more info they just sent the same screenshot. I wonder if it's something to do with iOS 14? I'm a bit lost if I can't replicate the problem...
This might be related -> https://developer.apple.com/forums/thread/651533

OS14.1 appears to have sign-in issues using a simulator. I suspect all the testers are using simulators because iPhones are too expensive :-D
@MarinoSch could you find a solution? We encounter the same problem.

We were unable to sign in to review your app with the demo account information you provided - But it works on our Testflight
 
 
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