Bot fails to establish call – 500#1203002 after Establishing (app-hosted media)

[keshavjeet]

Product: Microsoft Graph Cloud Communications API / Teams Calls & Meetings – Application-hosted media bot

Issue: Call joins (state: Establishing) but immediately terminates with Server Internal Error. DiagCode: 500#1203002. The bot never reaches state Established and does not appear in the meeting.

Request: Please confirm whether 500#1203002 indicates a service-side restriction or certificate/CA requirement for app-hosted media, and what we need to change (if anything) on our side.

3. Environment & Versions

Item	Value
OS	Windows (Azure VM)
.NET	.NET 8.0
Microsoft.Graph	5.103.0
Microsoft.Graph.Communications.Calls	1.2.0.15690
Microsoft.Graph.Communications.Calls.Media	1.2.0.15690
Microsoft.Graph.Communications.Client	1.2.0.15690
Microsoft.Skype.Bots.Media	1.33.0.258-preview
Hosting	Azure VM (Windows), app listening on HTTPS 443 and media port 8445

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4. Bot / Tenant Configuration (redact secrets)

Setting	Value
Tenant ID	df94721f-849a-4439-bac1-3575268e60f5
App (Client) ID	bf954344-4a7c-487f-8783-97ff96268da4
App Secret	(configured in app – do not include in ticket)
Bot base URL	https://vidur-bot-dns.eastus.cloudapp.azure.com
Callback URL	https://vidur-bot-dns.eastus.cloudapp.azure.com/callback
Media instance public IP	20.120.23.47
Media instance public port	8445
Media instance internal port	8445
Certificate thumbprint	63FAA24B9D6FA49304E865B6199B39DEF1AEDF8B
Certificate subject	CN=vidur-bot-dns.eastus.cloudapp.azure.com
Certificate key type	CSP (RSACryptoServiceProvider)

Graph permissions (application, admin-consented):
Calls.JoinGroupCall.All, Calls.AccessMedia.All (and any other calling permissions you have added).

Azure Bot / Teams channel:
Calling enabled; Webhook (for calling) = https://vidur-bot-dns.eastus.cloudapp.azure.com/callback.

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5. Error Details

Field	Value
Result code	500
Subcode	1203002
Message	Server Internal Error. DiagCode: 500#1203002.@
Call state when it occurs	Call is in Establishing, then transitions to Terminated with the above resultInfo.

Example call ID (from our logs):
25005d80-b798-4edc-bdc5-cb3fde570439
(You can include the most recent call ID from your logs.)

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[ssulzer]

@keshavjeet
One thing to check is the firewall on the bot's VM: does it allow outbound HTTPS/TCP back to the Teams IP address space? (52.112.0.0/14 and 52.122.0.0/15, any destination port?)

[lojoh]

@keshavjeet

Does this start working if you change to Microsoft.Skype.Bots.Media version 1.31.0.225-preview?

I get similar issues when trying to upgrade from 1.31.0.225-preview to 1.33.0.258-preview.
It works great with 1.31.0.225-preview but when using 1.32.0.70-preview or 1.33.0.258-preview its failing with no other code changes.
I reach state State=Establishing and then immediately get State=Terminated.

Call terminated. OldState=Establishing, NewState=Terminated, ResultInfo=code=500, subcode=1203002, message=Server Internal Error. DiagCode: 500#1203002.@, additionalData=none