Particle Electron wont connect

Hello

I have old particle electrons which have activated SIMs but will not connect to network after 24h (blinking green)

Is there anything I could try to troubleshoot this?

Try using the web device doctor.

However, if you are in the United States it likely will not be able to connect as 2G and 3G services have been shut down.

Darn - so these devices are basically useless in US