Surface can't sign into iCloud app

I have a client with a Microsoft Surface and he uses the iCloud app quite a bit. One day, he noticed that the app was asking him to sign in. He puts in his Apple ID and password and inputs the verification code from the 2FA.

After a few moments, he gets an error: Cannot sign in to iCloud. You cannot sign into iCloud because there was a problem verifying the identity of this Mac. Try restarting your Mac and signing in again.

A restart was performed with no changes. I had him sign into iTunes. Verification code was sent and he was able to pass the 2FA. I had him sign into iCloud.com. He was able to sign in and get passed the 2FA. Try the app again and got the error. I uninstalled the app and rebooted. Installed again and rebooted. Once back to the desktop, started the app again and tried to login and got the same error. I had him authorize the computer again in iTunes. Tried to sign into iCloud app again and got the error.

I've run DISM and SFC scans and made sure Windows 10 was up to date. I'm scratching my head why everything but iCloud can get passed the 2FA. The error doesn't make much sense to me since it's not a Mac. I'm out of ideas, curious if anyone else has something I can try. Thank you!