Bot fails to join the meeting when admitted by the host.

Describe the issue
Bot fails for joining the meeting after the host admit. ( Status shows "Leaving" and stays )
I cannot find the debugging point on this code and feels like I'am on the big-wall.
Seems the api cannot correctly parsing the teams-endpoint after signal-channel make a connection.

Code Snippet
fail: EchoBot.Bot.BotMediaLogger[0]
[AvMP][AppId:7dad7050-d982-418c-a16c-9d21a920868e][vm-aiarch-hdbot] TL_ERROR(TF_COMPONENT) [vm-aiarch-hdbot]12232.33::03/16/2025-23:48:11.024.00000001 (MPAZAPPHOST,LogError:AzAppMPHostLogger.cs(39)) TL_ERROR(TF_COMPONENT) [vm-aiarch-hdbot]12232.33::03/16/2025-23:48:11.023.00000072 (AVMP,GetAllChannelsQoe:Context.cs(7036)) ([cid:33fc2580-8215-4066-b318-2c0e9d031c17])[MP] GetAllChannelsQoe: context[3f0230e4-3444-43b2-910f-689f14535004] Endpoints not found

Expected behavior
Bot comes into the meeting after the host admits the request to participation

Graph SDK (please complete the following information):
PS C:\Users<>\workspace\microsoft-graph-comms-samples\Samples\PublicSamples\EchoBot\src\EchoBot> dotnet list package | findstr Microsoft.Graph

Microsoft.Graph.Communications.Calls 1.2.0.10563 1.2.0.10563
Microsoft.Graph.Communications.Calls.Media 1.2.0.10563 1.2.0.10563
Microsoft.Graph.Communications.Core 1.2.0.10563 1.2.0.10563

Call ID
Response Status Code: 200
Response Body: {"callId":"09008880-0b82-479e-a1ca-81814018e84b","scenarioId":"c409dd50-7ec7-4c3a-b1c8-4acd11dc925f","threadId":"19:meeting_YTJjYmFkM2UtNWVhZi00NjU4LWIzZjgtYjU2YTJmMzVjMDc3@thread.v2","port":"443"}
11:47:57 PM ( KST ) / 2:47:57 PM ( UST)

Logs
fail: EchoBot.Bot.BotMediaLogger[0]
[AvMP][AppId:7dad7050-d982-418c-a16c-9d21a920868e][vm-aiarch-hdbot] TL_ERROR(TF_COMPONENT) [vm-aiarch-hdbot]12232.33::03/16/2025-23:48:11.024.00000001 (MPAZAPPHOST,LogError:AzAppMPHostLogger.cs(39)) TL_ERROR(TF_COMPONENT) [vm-aiarch-hdbot]12232.33::03/16/2025-23:48:11.023.00000072 (AVMP,GetAllChannelsQoe:Context.cs(7036)) ([cid:33fc2580-8215-4066-b318-2c0e9d031c17])[MP] GetAllChannelsQoe: context[3f0230e4-3444-43b2-910f-689f14535004] Endpoints not found

debug output ( vscode )

Application Insights Telemetry (unconfigured): {"name":"AppTraces","time":"2025-03-17T02:01:44.9702466Z","tags":{"ai.cloud.roleInstance":"vm-aiarch-hdbot","ai.internal.sdkVersion":"il:2.22.0-997"},"data":{"baseType":"MessageData","baseData":{"ver":2,"message":"[AvMP][AppId:7dad7050-d982-418c-a16c-9d21a920868e][vm-aiarch-hdbot] TL_ERROR(TF_COMPONENT) [vm-aiarch-hdbot]12484.24::03/17/2025-11:01:44.965.00000001 (MPAZAPPHOST,LogError:AzAppMPHostLogger.cs(39)) TL_ERROR(TF_COMPONENT) [vm-aiarch-hdbot]12484.24::03/17/2025-11:01:44.964.00000073 (AVMP,GetAllChannelsQoe:Context.cs(7036)) ([cid:fc39a2ab-5bf6-4d46-9707-c1ba0d9fab1d])[MP] GetAllChannelsQoe: context[85ecb464-59fd-4dbb-b946-e2ca8af2e326] Endpoints not found","severityLevel":"Error","properties":{"OriginalFormat":"[AvMP][AppId:7dad7050-d982-418c-a16c-9d21a920868e][vm-aiarch-hdbot] TL_ERROR(TF_COMPONENT) [vm-aiarch-hdbot]12484.24::03/17/2025-11:01:44.965.00000001 (MPAZAPPHOST,LogError:AzAppMPHostLogger.cs(39)) TL_ERROR(TF_COMPONENT) [vm-aiarch-hdbot]12484.24::03/17/2025-11:01:44.964.00000073 (AVMP,GetAllChannelsQoe:Context.cs(7036)) ([cid:fc39a2ab-5bf6-4d46-9707-c1ba0d9fab1d])[MP] GetAllChannelsQoe: context[85ecb464-59fd-4dbb-b946-e2ca8af2e326] Endpoints not found","CategoryName":"EchoBot.Bot.BotMediaLogger"}}}}

Additional context
the test is being done on azure cloud vm with 4vcpu ( 2cores) and SSL certificates are created using certbot ( linux) and converted / stored on windows certstore.
Granted persmissions are follows.

• Calls.JoinGroupCall.All
• Calls.JoinGroupCallAsGuest.All
• Calls.AccessMedia.All
• User.Read

Tcp ports are tested and open ( 8445 and ngrok forwarded ports too. )

Start with the EchoBot sample and the BotMediaLogger output, then reproduce the host-admitted join using the listed Microsoft Graph Communications SDK packages. Trace the transition after the signal channel connects and investigate the reported "Endpoints not found" error. Done means the bot joins the meeting after admission without remaining in the Leaving state.