I have some GL7500 modems and a hologram SIM card. Initially, it was working but as a test I “paused” the sim and sure enough, the modem was no longer able to register (+CxREG: 3 -> denied). So I clicked “resume” for the sim and tried for a long time to get that modem to work again and it just wouldn’t - same registration denied state.
I thought I’d try another GL7500 modem and that one worked. So I thought, lets try this again - paused it, then resumed and now that modem still can’t register.
So my question is, is there some problem with “pausing” sim cards? It seems to blacklist whatever modem was using it when the pause occurred. Yet a new fresh modem can use the card.