Cannot sign into newly created Apple account created via Apple School Manager.

Cannot sign into newly created Apple account created via Apple School Manager. Well, it lets me sign in with the temporary password, asks me to create a new password, which it accepts, but on the next page load, it says "iCloud encountered an error while trying to connect to the server."

I've tried on multiple devices, on multiple networks. I'm able to sign into a personal Apple ID without issue, so it must be an issue with the managed accounts. Have tried multiple managed accounts, including newly created and existing accounts.

In Apple School Manager, managed accounts are allowed to sign into any devices, there are no restrictions that I can see for managed accounts.

I've tried on MacOS and also on an Apple TV so far.