am facing a very weird issue with a SIM800L GSM module. I am working on a project that involves connecting the SIM800L module to the NodeMCU, all of this is powered by a 3.7 V battery.
Problem: I have a SIM800L and I have a SIM card from a carrier that works fine in the module. I then got a new SIM from the same carrier and it worked fine for 2 weeks, but then one day I inserted the SIM in my phone to get an internet package.
After that I tried using it in the SIM800L and it doesn't work anymore; the LED keeps blinking indicating it can't find a network. When I put my old SIM in it, it still works.
There is no pin lock on either SIM. Both SIMs work fine in my phone, but only the old one works in the SIM800L. Both SIMs are from the same carrier, both SIMs support 4G, and 2G still works in the country I'm in.
What could be the problem?
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