Graph API implements paging for certain API. For List chat messages API, 20 message is the limit currently. The API response has "@odata.nextLink" property with the link to fetch next 20 messages.
Sample Response
"@odata.context": "https://graph.microsoft.com/beta/LongUrlShort/messages",
"@odata.count": 20,
"@odata.nextLink": "https://graph.microsoft.com/beta/me/chats/LongUrlhSort",
So you need to handle it while calling the API. You can make the API call in loop and get all the records.
Thanks,
Prasad Das
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