Microsoft Graph API Error 9999 when joining Teams meeting with AppHostedMediaConfig

Question

Problem

I'm developing a Microsoft Teams bot using application-hosted media to join meetings and capture audio. The bot successfully authenticates and passes all permission checks, but fails when attempting to join a meeting with Error Code 9999 from Microsoft Graph Communications API.

Error Details

• Error Code: 9999
• Message: Unknown internal server error
• Request IDs:
  • d59085b6-9777-4106-a6a4-f109b10240d8
  • e05889a8-7430-4717-b320-30b242cba4b9

Configuration Verified

✅ Authentication: Token acquired successfully with all required permissions (Calls.JoinGroupCall.All, Calls.AccessMedia.All, etc.)

✅ Network: TCP port 8445 is accessible from internet (verified with Test-NetConnection)

✅ Callback Endpoint: https://unterrible-dewitt-gametically.ngrok-free.dev/api/callback returns 200 OK

✅ Certificate: CSP format certificate installed (thumbprint: 1503F39C188A705F75A0C59D558573896F934145)

✅ SDP Offer: Generated correctly with valid certificate fingerprint

✅ Media Platform: Initialized successfully on MediaBot server

Code Pattern

Using official Microsoft Graph SDK pattern:

var call = new Call

{

Direction = CallDirection.Outgoing,

CallbackUri = "https://unterrible-dewitt-gametically.ngrok-free.dev/api/callback",

ChatInfo = new ChatInfo

{

    ThreadId = "19:meeting_xxx@thread.v2",

    MessageId = "0"

},

MeetingInfo = new OrganizerMeetingInfo

{

    Organizer = new IdentitySet

    {

        User = new Identity { Id = organizerId }

    }

},

TenantId = tenantId,

RequestedModalities = new List

Answer 1

Error code 9999 in the context of Microsoft Graph Communications API typically indicates an unknown internal server error. Unfortunately, the specific details regarding this error in relation to AppHostedMediaConfig are not explicitly documented in the available resources. However, here are some general considerations that may help you troubleshoot the issue:

1. Error Code 9999: This error is often indicative of an internal issue that may not be directly related to your implementation. It could be a temporary issue with the Microsoft service or an unhandled exception in the backend.
2. Validation Requirements: While there are no specific additional validation requirements mentioned in the context, ensure that all configurations, especially related to media endpoints and SDP offers, are correctly set up. Double-check the SDP offer format and ensure that the media server is configured properly.
3. DTLS Handshake: Microsoft Graph does validate the DTLS handshake as part of the media negotiation process. Ensure that your media server is correctly handling DTLS and that the certificates are valid and properly configured.
4. Known Issues: There may be known issues with application-hosted media for bots, but specific details would typically be found in the Microsoft documentation or support forums. It may be beneficial to check for any updates or known issues related to the SDK you are using.

For further assistance, consider reaching out to Microsoft Support if the issue persists, especially since you are receiving an internal server error which may require their insight to resolve.