Meeting request received as play email instead of calendar format M365

Hi @Priya Jayaraman

Based on your description, the meeting invitation is being received as a regular email with .htm and .txt attachments.

From my research, ATT files can appear when a meeting email is modified during delivery (e.g., by mail filters or security gateways).

If the original calendar invite format is altered or stripped, Outlook cannot recognize it as a meeting request and shows it as a normal email with .htm or .txt ATT attachments instead.

To help narrow down, could you please confirm:

• Whether this issue occurs with all meeting invites or only from a specific sender?
• Is the sender internal or external user?
• Check that specific email if it appears correctly in Outlook Web (OWA)
• Any other user in your organization faces the same issue.

In parallel, I recommend checking if any mail flow rules or any filtering systems might be modifying incoming meeting messages.

I look forward for your reply.

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