findMeeting REST API does not support shared mailbox?

Hi RashmiRahul​!
Hope you are doing well!

Thank you so much for sharing your question with us — and for outlining your scenario so clearly.

This seems to be relevant to what you're observing: the Outlook Calendar REST API you're using seems completely retired, and Microsoft officially decommissioned the v2.0 endpoints.

When technologies reach deprecation, it’s common for certain operations to gradually stop working as the ongoing services evolve and new technologies are integrated, and some functionality may become limited or no longer available.

For your reference, here are Microsoft’s official announcements on this deprecation:

🔗 [DEPRECATED] Use the Outlook REST API (version 2.0) | Microsoft Learn
🔗 Outlook REST API v2.0 and beta endpoints decommissioning

To help you verify what is currently supported and explore alternative approaches, you can check the official Microsoft Graph support area:

🔗Microsoft Graph | Support

You can also use Microsoft Q&A — and simply select the product or technology area that best applies to your case‑scenario:

🔗Microsoft Q&A | Microsoft Learn

Both resources can help you confirm what is expected behavior today and what options may be available depending on your implementation.

I hope this helps, and feel free to reach out to us anytime!

Thanks a million!😊