Thank you for posting this in Microsoft Q&A.
I understand you are trying to invite guest users but getting error "Invitations are blocked for this directory due to suspicious activity. Please contact Microsoft support for help".
The issue you encountered was caused by attempting to invite bulk guest users
We appreciate you for sharing your tenant details over email. We addressed this by collaborating with our internal Product Group team, who have now unblocked your tenant. As you've mentioned, you can now access it successfully.
Hope this helps. Do let us know if you any further queries.
Thanks,
Navya.
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