Some of my gps devices are not reporting

Since 2 days ago, the GPS devices approximately 60 out of 80 stopped reporting to the platform, I checked the server and everything is fine. I contacted the telephone company and their network is also fine, what could it be ?

Logicly you first check traccar log for errors and if it actually received data from those offline device.

Would try to restart the server. Then restart traccar server.

Logicly also check if the simcard is working / has data etc..

Check if no firewall is blocking the device port. Check if the port is open from the internet.

I see even you stopt updating :)