GL-XE3000: SIM card not registered , but SIM does work well in Mudi (v1)

rince

HI there,
I just bought a GL-XE3000 for using it with my SIM-Card for 5G-usage. the SIM-card worked flawlessly within my Mudi (v1)-modem, where it connected happily with it’s connectivity Provider (German) Telekom.

On the new model I only receive “SIM card not registered”. I can switch the SIM back to my Mudi-Router and I get good LTE-connection, so there is no locking on the SIM-card itself. I tried the SIM card within my iPhone 12 Max and it was able to connect with an 5G-Connection, so the plan supports LTE.

what can I do to locate the problem? on luck I see that the modem has an unsupported protocol type, but there is no luci-proto-Package offered. I do not know whether this is needed.

Admin Panel Version is 4.0, latest firmware installed, Kernel version 5.4.211. OpenWRT is 21.02.SNAPSHOT r15812+879-46b6ee7ffc.

best regards, Hanno