Can't activate Macs after wipe du to old certificate

I've seen this before and it was that the device needed a firmware update but couldnt download it.

Does your wifi have SSL inspection and not all Apple URLs are whitelisted? Try connecting the device using a mobile hotspot to see if thats the issue.

In this case I don’t think it has to do with firmware. I’ve reset about 20 Macs today in same batch and now it seams to work. Using the same Wi-Fi as last week. 

Is the APNS / Apple Push notification certificate in your Jamf Pro updated? It sounds like it might be expired and in need of renewal.

All certificates are up-to-date. Seams to work as it should today, but I didn't Friday last week. We haven't done any changes.

Good it got resolved. The only thing I could think of would be a local network certificate that was automatically or remotely updated. Try to pull logs from the devices affected for later investigation.

The problem is not really solved. When the problem occurred, we were at school A and connected to the guest network. The following week we were at school B and connected to the same guest network where it worked.

Today I was down at school A again and tried - still not working there. Took a computer with me up to my office which is in another building, there it works perfectly just like in school B.

Currently, we only have one firewall for all buildings. But we have a lot of access points around the buildings. Anyone experienced the same problem and know what could be causing it?

Pull network logs for an affected device at the time of the event. Worst case, gather diagnostics logs from the device and start a case with Apple Support. In my experience, these cases are best dealt with using Feedback Assistant on a Mac. Also, I would try to renew the APNS certificate and DEP/ADE token regardless of validity. 

My two cents are on network, but never stop thinking wide before it has been definitely isolated to that. Is enrolling from a home network an option? Try if possible.

With pulling network logs, do you mean from the affected device or anything else?