We have used the modem TRB145 and my own SIM-card for test purpose, communication to the meter works OK.
Now we have used a SIM-card from one of our customers together with a test meter in my office, seems that communication does not always work correct to our customers HES system.
Is it possible for you to make a Teams session and verify that I have made the settings in the modem correct?
Problem could be related to our customers HES system but it could be useful to have the modem settings verified.