EM12-G module has ims problems

IoT Modules LTE-A Module
1

Hello
I have had a problem on an EM12-G Module. When switching from the 3G to the 4G network, the ims service does not work, and so, calls are impossible.
I have tried to force the registration to the service, with AT+QCFG=“ims”,1
Then, asking AT+QCFG=“ims” gives the answer 1,0. However, it should give 1,1 in order to allow VoLTE calls.

Has anyone had the same problem? If so, is there a way to solve?
Thanks in advance

2

What do the following AT commands return?

AT+QMBNCFG="List"
AT+CGDCONT?
AT$QCPDPIMSCFGE?