I'm building a tool in which I need to send more than 2 messages in the same thread (the message have identical subject & recipients) using Microsoft Graph API with some interval of days between them.
The problem is that I cannot send a message in the same thread using the API, even though the subject & recipients are same, Outlook displays them as different threads (but on the recipients' side (Gmail side) - they belong to same thread).
I tried using conversationId (which I got in the first message) in the second message but they still ended up showing in different threads.
Is there any way in I can send messages in the same thread?
According to your description, I assume you want to use the https://graph.microsoft.com/v1.0/groups/{id}/threads endpoint to send more than 2 messages in the same thread.
Refer to this document,
A new conversation, conversation thread, and post are created in the group. Use reply thread or reply post to further post to that thread.
So we can use the replay endpoint to send message in the same thread.