Cannot initiate PSTN calls from bot

Nivedipa-MSFTHi Nivedipa,

I could solve the "InternalServerError" by using following c# code:

AdditionalData = new Dictionary<string, object>()
{
    {"phone", new Identity() { Id = pDevice} }
}

instad of

AdditionalData = new Dictionary<string, object>()
{
    {"phone", "{\"@odata.type\":\"#microsoft.graph.identity\",\"id\":\"+12345678901\"}"}
}

But now I have annother problem: After sending the MakeCall Request I get an establishing Event and immediately an Terminated Event with an Error:

"value": [
{
"changeType": "Updated",
"resourceUrl": "/communications/calls/911f6100-723b-400b-9053-893f686f3131",
"resource": "/app/calls/911f6100-723b-400b-9053-893f686f3131",
"resourceData": {
"@odata.type": "#microsoft.graph.call",
"state": "establishing",
"callChainId": "ef0c7f6a-974b-4700-8525-d74fe4d924c2"
},
"@odata.type": "#microsoft.graph.commsNotification"
}
],
"@odata.type": "#microsoft.graph.commsNotifications"
}

{
"value": [
{
"changeType": "Deleted",
"resourceUrl": "/communications/calls/911f6100-723b-400b-9053-893f686f3131",
"resource": "/app/calls/911f6100-723b-400b-9053-893f686f3131",
"resourceData": {
"@odata.type": "#microsoft.graph.call",
"state": "terminated",
"resultInfo": {
"@odata.type": "#microsoft.graph.resultInfo",
"code": 500,
"subcode": 9999,
"message": "Get Outbound routing - failed getting userId from billedUserMri: 28:d86f4970-a209-46f1-ad06-87137338eac2. DiagCode: 500#510543"
},
"callChainId": "ef0c7f6a-974b-4700-8525-d74fe4d924c2",
"terminationSender": {
"@odata.type": "#microsoft.graph.identitySet",
"phone": {
"@odata.type": "#microsoft.graph.identity",
"id": "+41*********",
"displayName": "4:+41*******",
"identityProvider": "None"
}
}
},
"@odata.type": "#microsoft.graph.commsNotification"
}
],
"@odata.type": "#microsoft.graph.commsNotifications"
}

The service user for the bot has an "Microsoft 365 E3" and a "Microsoft 365 Phone System" license.

And I am able to make call from a PSTN number to the bot.

Any idea?

Regards

Gerd