Had very similar issues, then found the enrolment URL had change from and N172 to an N880 based one.... only spotted this in the login URL. Now all working. Why did this change???? ... View more

As stated above, stacking is simple and will make your life easier. The downside of which is that during a firmware upgrade, the stack reboots as a whole resulting in a network outage for connected devices. If that's feasible for your business to manage then IMO, stacking would be the way to go. ... View more

Try applying the "Allow list" group policy to a phone.  This allows everything and nothing is blocked.   If the phone works - you know it is something in your Meraki configuration.  If the phone does not work - you know it is something to do with the phone/Intune configuration.     ... View more