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Hello, we have a tenant to authorize guest users to access apps hosted in our main tenant
We've been using the new tenant for about a month to test guest user access and prepare for go-live, and up until today the process has been 100% successful.
This morning, we tried adding around 600 users in bulk, but the operation failed after about 200 users with the message "Error! Invitations are blocked for this directory due to suspicious activity. Please contact Microsoft support for help."
We are now unable to invite guest users at all. When we attempt to invite one manually, we receive "Insufficient privileges to complete the operation" errors.
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Hello @Brian King (Apps2) ,
As part of security enhancements, Microsoft will have anomaly detections which checks if unusual invites are occurring from any tenants and based on that anomaly detections the tenant will be blocked.
The customers which tenant was created within 30 days can be blocked by bulk invitation >= 500 in 24 hour.
To Proceed further I have pinged you in the private message. Please send those details.
let us know if you have any queries. Happy to assist you further.
Thank you for the fast response! I have replied to your PM.
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Hi @Brian King (Apps2),
The error message "Invitations are blocked for this directory due to suspicious activity" indicates that Microsoft has temporarily disabled guest invitations for your tenant due to detected unusual activity. I recommend that you submit a support ticket to Microsoft Support and provide details of your tenant to help the support team unblock your tenant.
Thank you Lizzy. I submitted a support ticket approximately 7 hours ago and have not yet heard back. I am hoping the information I provided Goutam will help resolve the issue.
Hello @Brian King (Apps2) ,
As you shared the tenant details via private message, I have involved the Product Group team to remove the Invitation block for your tenant. We are working actively on it once the block is removed, I'll provide you with an update here.
Let us know if you have any additional queries. Happy to assist you further.
Thank you! We need to prevent this from occurring again, so is there a setting we can change to allow us to invite the remaining guests without disruption?
Hello @Brian King (Apps2) ,
There is no such setting available. You can continue using it as usual once the tenant is unblocked from the product team.
Let me know if you have any additional queries. Happy to assist you further.
is there documentation available that describes the invitation sending limits? We'd like to understand the cause and how to avoid it going forward.
Hello @Brian King (Apps2) ,
Unfortunately, there is no official Microsoft documentation available regarding this issue. However, as mentioned earlier, the error "Invitations are blocked for this directory due to suspicious activity" is related to Microsoft’s security enhancements. Microsoft uses anomaly detection to monitor for unusual invitation activity across tenants. If such activity is detected, the tenant may be temporarily blocked.
Specifically, for tenants created within the last 30 days, sending 500 or more invitations within a 24-hour period can trigger this block. It’s recommended to keep this in mind to avoid similar issues in the future.
Regarding the current issue, our internal team is actively working on it. I will provide you with an update as soon as the invitation block has been lifted.
let us know if you have any queries. Happy to assist you further.
Hello @Brian King (Apps2) ,
Thank you for sharing the details for the issue.
Based on the error message you received it appears that was Invitations are blocked in your tenant due to suspicious activity.
We addressed this by collaborating with our internal team, who have now unblocked your tenant.
You can check and confirm whether you were able to access the tenant which was blocked.
Hope this helps. Let us know if you have any queries. Happy to assist you further.
Thank you Goutam. We are able to successfully invite guests now. Thank you so much for your assistance.