Hi @silvia
I have checked again the antenna connections of the modem and they are correctly connected. The base station is in the same office as where the modem logs were captured, 10 meters away where other modem pick up a strong signal from the same 5G network and base station.
With the modem RG255C-GL and the command AT+QSCAN=2 the signal from the 5G SA network seems to be very good:
AT+QSCAN=2
+QSCAN: "NR5G",999,70,469970,500,-62,-11,79,1
+QSCAN: "NR5G",999,70,476210,4,-54,-11,86,1
When trying to connect to a commercial 4G network with the modem, it can connect without any problems and gets a good signal.