We are using a Twilio SIM with the RAK7258. The SIM uses T-Mobile carrier service here in the USA. When we enable LTE, it connects briefly and then disconnects, repeatedly. In the system log it shows:
Wed Dec 18 20:01:04 2019 kern.info quectel-CM[16868]: requestRegistrationState2 MCC: 310, MNC: 260, PS: Attached, DataCap: LTE
Wed Dec 18 20:01:04 2019 kern.info quectel-CM[16868]: requestSetupDataCall QMUXResult = 0x1, QMUXError = 0xe
Wed Dec 18 20:01:09 2019 kern.info quectel-CM[16868]: requestRegistrationState2 MCC: 310, MNC: 260, PS: Attached, DataCap: LTE
Wed Dec 18 20:01:09 2019 kern.info quectel-CM[16868]: requestSetupDataCall QMUXResult = 0x1, QMUXError = 0xe
The SIM works fine in other equipment. Also a different SIM (from our local AT&T mobile carrier) works fine in the RAK7258. Any ideas on why the Twilio/T-Mobile SIM is not working, or what we could try to fix it?