Lora E5 - Multicast and GenAppKey

Hello, this is the situation: we are trying to make multicast working in class-c with ChirpStack network server. We managed to switch the device in class C with AT+CLASS=C, in fact the reception of unicast message works perfectly (pre.
When trying the multicast mode setting McDEVADDR, McNWKSKEY, McAPPSKEY and COUNTER with the following command:

AT+LW=MC,ON,“7f0df806”,“xxxxd01a4490ee18e81efab0ae3bxxxx”,“xxxx69ce10aac0570399174c8637xxxx”,0

The command succed, but when sending a multicast message nothing is received by the lora node.

We’ve tried also with aws IoT network server: there is a field where to insert GenAppKey, but i don’t understand if LoraE5 support this GenAppKey. There are no way to insert McDevAddr, McNwkSKey, McAppSKey in aws IoT: only GenAppKey.

I think the problem is on the node.
What can you suggest to debug this problem?
Does anybody managed to make the multicast working?

Gateway is Conduit MTCDT 6.0.1 that supports multicast.

Thank you in advance.