EG21G VoLTE not working

Hi, I am working with a EG21-G module on a custom board and we need to enable the VoLTE.

The module is working fine with the 2G voice calls and also with data connection.

To enable the VoLTE, I used the following commands:

AT+QMBNCFG=“Autosel”,1
AT+QCFG:“volte_disable”,0
AT+QCFG: “ims”,1
(optional AT+CFUN=1,1 to apply the modification, not clear if it is mandatory)

but the read command

AT+QCFG:“ims”

always returns

+QCFG: “ims”,1,0

indicating the the VoLTE is not active.

I also noticed that the module somehow auto created some profiles (2 and 3)

+CGDCONT: 1,“IP”,“web.ho-mobile.it”,“0.0.0.0”,0,0,0,0
+CGDCONT: 2,“IPV4V6”,“ims”,“0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0”,0,0,0,0
+CGDCONT: 3,“IPV4V6”,“SOS”,“0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0”,0,0,0,1

But never activate them by itself:

+CGPADDR: 1,“<my_ip>”
+CGPADDR: 2,“0.0.0.0,0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0”
+CGPADDR: 3,“0.0.0.0,0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0”

I tried to manually force the activation of the ims profile, obtaining an IP, but nothing changed for the VoLTE.
I deleted the 2 profiles as test and they are not restore by the module anymore.

Do I miss any additional configuration?

I leave some additional information:
Quectel
EG21
Revision: EG21GGBR07A11M1G

+CREG=0,1
+CEREG: 2,1,“6980”,“0B81F0B”,7
+COPS: 0,0,“ho. ho.”,7 (“ho mobile” italian operator)

AT+QMBNCFG=“LIST”
+QMBNCFG: “List”,1,1,0,“ROW_Generic_3GPP”,…
+QMBNCFG: “List”,0,0,0,“VoLTE-ATT”, …
[…]

Thank you

Does this SIM card volte normally on your phone? Or you can try another SIM card

Yes, VoLTE works fine on a smartphone with the same SIM.

I have to verify with another SIM.

I verified with another VoLTE-enabled SIM: same result.

Any suggestion?

Thank you

pls run
AT+QNVFR=“/nv/item_files/ims/IMS_enable”

and provide the result for me

Here is the response:

AT+QNVFR=“/nv/item_files/ims/IMS_enable”

+QNVFR: 01