Hello @Sergey Tihon
Thanks for your patience and understanding.
This error message seems to be common for Graph API and Teams app as it says API requires one of 'OnlineMeetingTranscript.Read.All, OnlineMeetingTranscript.Read.Chat' permissions. I'm also getting the same error using List Transcripts Graph API with application token (without consenting 'OnlineMeetingTranscript.Read.All' permission in Azure app). Please note that 'OnlineMeetingTranscript.Read.Chat' is a Resource-specific permission and Resource-specific permissions are only available to Teams apps installed on the Teams client and are currently not part of the Azure Active Directory (AAD) portal, so you wouldn't be able to find them in AAD portal. Moreover, as per the graph side, for listing transcripts we need atleast OnlineMeetingTranscript.Read.All permisson as documented here.
Hope this helps.
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