SIM active but won't connect on known good HW/FW.

I recently activated a new SIM and it shows as “active” on my dashboard. It has a plan and I have a positive balance. However, my hardware will not connect with it. If I remove the new SIM and insert an older SIM (also active and positive balance) the hardware works perfectly. No change in hardware or code - literally the only change is to remove new SIM and insert old SIM and it works. Putting new SIM back in makes board fail to connect.

The SIM plans are different:
Old SIM: Pilot Plan
New SIM: Professional Plan Flexible Data

Would this matter?
I believe the hardware is irrelevant here, but it is a Botletics SIM7000G and Arduino Uno.

What can I do to troubleshoot this?

Are you able to run AT commands?

If so run through https://help.hologram.io/en/articles/1944384-modem-sim-annotated-diagnostic-test and post the results.

The Professional plan should work everywhere the Pilot Plan works as far as I’m aware, the above AT commands will help isolate exactly what is going wrong.

You can also double check that the sim is active and you have credit on your account (the sim will be paused if you run out of funds).

Lastly, if this is the first time the simcard is being used, try leaving it in and powered on for 1-3 hours (overnight if possible) and it may connect. There is a post by Hologram some while ago that notes the first registration on Cat-M1 networks may take ~ 1 hour.

Thanks for the link. The AT testing showed the non-working SIM was receiving and saw networks, but was still in search mode not registering with any. I used AT+COPS to force it to select a network. Now it registers on every power up. I don’t remember having to do this before. The preferred network must be saved on the SIM?

The other odd thing is that the SimCom 7000G module reports AT+CSQ=99,99 (no signal) even when it shows it sees networks as reported by AT+COPS=?. I suppose this is because it can’t report RSSI for all of them, so it reports no signal. This actually threw me off for several days thinking a board was bad until I tried working and non-working SIMs in the same board.

Issue resolved. Thanks for your help!