Similar to this ticket, we are no longer able to connect to Verizon using a Hologram SIM after upgrading modem firmware from 1.0.1 to 1.1.0.
I'm attaching a matching console log and modem trace showing a connection attempt using at_client.
Recommend you reach out to Hologram. There have been changes recently that affect roaming SIMs (like Hologram) from accessing Verizon towers (specifically CAT M1, I believe). We were impacted as well, beginning in late November 2019.
You are likely right. I tried jumping the modem back to firmware 1.0.1 to see if it corrected the issue and it doesn't. I think it was just coincidental that the first time I had tried this in over a month was right after upgrading firmware. I will contact Hologram.
Have you heard back from Hologram?
According to the log, the UE gets "PLMN not allowed" error during attach to the Verizon network. This means that the Hologram SIM does not allow roaming to Verizon.