Microsoft Graph API: adhocCalls transcripts returns 501 NotImplemented, getAllTranscripts returns empty arrays

Question

Issue Summary

I'm trying to retrieve call transcripts via Microsoft Graph API and encountering two issues:

1. adhocCalls endpoints return 501 NotImplemented
2. getAllTranscripts returns 200 OK with empty arrays for calls that exist in our tenant

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Environment

• Auth: Application permissions (client credentials flow)
• API Versions Tested: Both v1.0 and beta

Permissions Configured

• CallTranscripts.Read.All
• CallRecords.Read.All
• CallRecordings.Read.All
• OnlineMeetingTranscript.Read.All

---

Issue 1: 501 NotImplemented

Request:

GET https://graph.microsoft.com/v1.0/users/{userId}/adhocCalls/{callId}/transcripts
```**Response:**

```json
{
  "error": {
    "code": "NotImplemented",
    "message": "Failed to process request."
  }
}
```This occurs for both v1.0 and beta endpoints, despite the API being documented at:
https://learn.microsoft.com/en-us/graph/api/calltranscript-get

---

## Issue 2: Empty Arrays

**Request:**

```yaml
GET https://graph.microsoft.com/v1.0/users/{userId}/onlineMeetings/getAllTranscripts(meetingOrganizerUserId='{userId}')
```**Response:** 200 OK with "value": []

The calls DO exist - we can retrieve call records via /communications/callRecords/{callId} successfully.

---

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## What We've Verified

- Application Access Policy configured via PowerShell
- Teams Admin transcription policy enabled
- Call records accessible via Graph API
- Tested with multiple call types (ad-hoc Teams calls, PSTN calls)

Any guidance would be appreciated!

Answer 1

Hi @Vitalikarmanov,

Welcome to Microsoft Q&A, and thank you very much for reaching out to us.

Note that as Q&A moderator, I do not have access to your tenant configuration, and my testing environment is limited. So I can only be able to support you through available documentation and resources. That said, I will try to assist you as much as possible.

Based on your description, you’re calling the ad hoc call transcripts endpoint:

GET https://graph.microsoft.com/v1.0/users/{userId}/adhocCalls/{callId}/transcripts

Could you please confirm whether you intended to retrieve a specific transcript instead based on the Microsoft documentation?

According to Microsoft documentation, NotImplemented error (HTTP 501) generally means the service doesn’t support the requested feature in the current context, either because the request is targeting an unsupported endpoint/operation, or because the backend capability isn’t yet available or fully rolled out for that API scenario.

As I checked, the adhocCall surface is still relatively new, as it was introduced first under the preview (/beta) APIs on 27 October 2025. So practical examples and community references can still be limited compared to more established Graph areas. If the URL in your request contains any typo or mismatch, the best next step is to rewrite it to match the exact request format shown in Microsoft’s official documentation for this API.

For the getAllTranscripts call, based on the Microsoft Graph documentation, the API call you using: onlineMeeting/getAllTranscripts is intended for scheduled online meetings (onlineMeeting) and won’t return ad hoc call transcripts. If your goal is to retrieve all transcripts for ad hoc calls, you should use adhocCall/getAllTranscripts instead.

Additionally, please note that the adhocCall and adhocCall/getAllTranscripts endpoints originated in /beta (preview) and aren’t recommended for production, as preview APIs can change, be paused for maintenance, or be flighted/rolled out unevenly without notice, which may lead to unexpected or inconsistent behavior.

This summary is based on my findings from the community and several relevant threads. However, it may not accurately reflect the behavior in question. To help you reach your goal more effectively, I recommend posting a thread on the Microsoft Tech Community forum. It’s a great platform for deeper technical discussions and connecting with individuals who have hands-on experience and expertise. They’re best positioned to provide guidance and valuable insights on this topic.

Thank you for your understanding.

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