The following picture shows the Multicast network session key, the Multicast application session key, and the McKey of the nodes that I set myself. However, even after the settings were completed, multicast communication still couldn't be carried out after Time2SessionStart. I would like to know if there are any requirements for the setting of these three keys?
Please note that the MCKey is used to derrive the Multicast McNwkSKey / McAppSKey. Therefore, at the ChirpStack side when creating the multicast-group, you only have to configure the Multicast McNwkSKey / McAppSkey.
Using the Remote Multicast Setup protocol (I assume that is what you are using to make the device aware about the multicast-session), you send the (encrypted) MCKey to the device. The device will use this key to then derrive the Multicast McNwkSKey / McAppSKey using the following scheme:
