We face a situation where we send SMS using EC-25 and after sending some messages, we will get Error 350 when awaiting telco response to send SMS. It will not recover until like 2-4 hours later and will work and encounter the problem again. We are using Linux and telco in India Airtel. This is in 4G. Please advise.
Make sure that the module is registered under LTE, after adding the network, send AT+QCFG=“ltesms/format”, 1 and then send: AT+QCFG=“ltectcc/smsstorage”, 1 and then you can refer to the command set to send text messages normally.