That explains it. The Accept / Tentative / Decline buttons only appear if the invitation follows Microsoft’s Exchange / Outlook calendar format or if the connected account supports full calendar integration through Microsoft’s API. So if your account is Gmail, Yahoo, or another IMAP provider and you’re using the new Outlook, meeting invitations may appear as plain emails, no buttons. Don't worry this can still be fixed, here are your options:
Option 1: Switch back to Classic Outlook (recommended)
The classic Outlook app has native calendar parsing for Gmail, IMAP, and Exchange.
Option 2: Add your account’s calendar directly to its native service
If it’s a Gmail or Google Workspace account:
- Open your Gmail in a browser.
- Go to Google Calendar → you’ll find your meeting invites there with Yes / No / Maybe buttons.
- Respond there. It will still sync to Outlook (depending on your account link).