Microsoft Graph API group calling feature not working as expected

[Anmol14793]

When calling the Graph communications API for initiating a group call with service hosted media (https://docs.microsoft.com/en-us/graph/api/application-post-calls?view=graph-rest-beta&tabs=http) example-3, The call is in establishing state and the participants get the incoming call from the bot, but it gets disconnected automatically before the users can accept the call. Snippet of the API call is given below.

var callResponse = await axios({

    method: 'post',

    url: 'https://graph.microsoft.com/beta/communications/calls',

    headers: {

        'Content-Type': 'application/json',

        'Authorization': authToken

    },

    data: {

        "@odata.type": "#microsoft.graph.call",

        "direction": "outgoing",

        "subject": "Create a group call with service hosted media",

        "callbackUri": "https://d1a8b1330.ngrok.io",

        "source": {

            "@odata.type": "#microsoft.graph.participantInfo",

            "identity": {

                "@odata.type": "#microsoft.graph.identitySet",

                "application": {

                    "@odata.type": "#microsoft.graph.identity",

                    "displayName": "some-bot",

                    "id": "Bot app ID"

                }

            }

        },

        "targets": [{

                "@odata.type": "#microsoft.graph.invitationParticipantInfo",

                "identity": {

                    "@odata.type": "#microsoft.graph.identitySet",

                    "user": {

                        "@odata.type": "#microsoft.graph.identity",

                        "displayName": "User 1",

                        "id": "User 1 AAD object ID"

                    }

                }

            },

            {

              "@odata.type": "#microsoft.graph.participantInfo",

              "identity": {

                "@odata.type": "#microsoft.graph.identitySet",

                "user": {

                  "@odata.type": "#microsoft.graph.identity",

                  "displayName": "User 2",

                  "id": "User 2 AAD object ID"

                }

              }

            }

        ],

        "requestedModalities": [

            "audio"

        ],

        "mediaConfig": {

            "@odata.type": "#microsoft.graph.serviceHostedMediaConfig",

            "removeFromDefaultAudioGroup": false

        },

        "tenantId": "Tenent ID"

    }

});

Please send help ASAP.