I installed Google Classrooms first on my phone (Android 6.0.1), but I was not able to add an google account to use the app. It says "couldn't add account to google classroom. please try again or use a different account". I tried un-install and re-install many times with no luck.
However, I was able to install the same app on the other two devices (Android 7.1.1 and Android 5.0.2) and add the same account to the app.
Later, I noticed a different installation behavior on the fist device v.s. on the other two devices: during installation on the first device, it did not ask for permissions such as to check installed programs, use camera, etc. but those permission were asked when installing the app on the other two devices. I suspect that could be the reason why the app on the first device is not working (not able to add any account).
Did anyone encounter similar problems before? why do we see two different installation behaviors of the same app?