We are seeing the same thing, which started yesterday for us. When we look at the certificates area under Settings > General > VPN & Managed Devices > Jamf School MDM Profile, we have 3 expired certs showing up (root.edu..., leader.edu..., and member.edu...) I created a Jamf School support ticket last night about the issue and added info this morning about these expired certs. We have ~5000 classes so I'm not about to go in and adjust the description for each class to get the certificates to be refreshed/regenerated.
Ben in the Jamf School support group responded to my ticket that they "made a slight change on the backend of your Jamf School instance that should resolve that error message". After doing a device refresh against all of our devices, we checked with a few teachers and all of them are reporting that Apple Classroom is now working again. Hopefully you have opened a similar support ticket and can ask them to do the same thing for you that they did for us. (Since I'm not sure what they did, I'm guessing that if you reference our ticket number 107108, they can look to see what they did.)
Issue is still showing up intermittently at our school. Changing just one thing in any class, such as a description, makes it go away. (I had an iPad showing "you need a valid education profile" and after hitting refresh /save in the classes section after altering one description of JAmF classes showed up on said iPad almost instantaneously. But this can't be a viable solution.
We had an open ticket, JamF made changes, pushed a new certificate or some such and problem went away for a couple of days. Showed up again today. Removing and adding a student resolved the issue again but this can’t be a permanent solution. Our usual classroom fix for students not showing up was turning bluetooth and Wi-Fi off and on again, this doesn’t work anymore. Hard reset of students’ and or teachers device sometimes still helps but all in all the system is flaky.
We are experiencing this today as well. I contacted Jamf and they are working on a resolution on the backend. I did notice that to resolve it if the numbers are low (like one or two) I just quickly change the owner of the device to another student/teacher in that particular grade level (or however you have your devices grouped), and then back to the correct owner and it pushes out a new Education profile and that seems to resolve it. I am thinking this is tied to the update to 15. We had it blocked for students and teachers and just opened it up last week - now that our devices are running the update it seems to be causing the issue.
For anyone still having this issue I'll offer the workaround we implemented. Jamf support said to unassign and reassign the user, or enrol them in a new class so that their device will get a new EDU profile.
We created a smart group based on OS version 15 or higher, then created a new class manually in jamf and scoped it to the smart device group.
Now after a student (or teacher) updates their iPad, they are added to a new class and the device receives a new EDU profile. So far this appears to be working.
Huge problem at our Schools as well. We have 7000 classes and 13000 iPads. And it all started when iOS 15 was launched. Jamf told me to uncheck Apple Education support , wait a few hours and then Re-check. It did push out new EDU profiles but... Today it started again. I'm going to assume some of the students updated to iOS 15 today and now i might have to uncheck the ED support again. But its a pain and I hope they fix this.