High Priority - New Tenant - Cannot invite external guest users

Question

High Priority - New Tenant - Cannot invite external guest users

Anonymous

Hi !

My organization wanted to create a New Tenant to run some temporary workloads for a Hackathon and which could potentially serve as a Proof of Concepts for some AI use cases.

We are utilizing Terraform to test and provision everything in an automated manner.
This has likely triggered the anomaly detection of Microsoft and we have been barred from inviting more users.
We want to invite from a different directory, a total of about 30-35 users.

Would someone be able to support with this from Microsoft?

Please note that I have Global Admin access, no policies conflicting, no administrative units, etc.
I will message you the details of the tenant (tenant ID) and/or any other information you may require to solve this issue.
It is of high priority due to time limitations. Please support with this asap.

Best,
Klaudio

Anonymous

2026-04-22T15:12:43.9866667+00:00

Since it is a new tenant, not the core one, we don't have a Microsoft priority support, so we are stuck to posting this issue here.
Thanmayi Godithi 11,905 Reputation points Microsoft External Staff Moderator

2026-04-22T15:50:40.7033333+00:00

Hi Klaudio, Thank you for reaching out to Microsoft Q&A.

As part of its security enhancements, Microsoft has anomaly detection systems in place to identify unusual activity, such as an unusually high number of invitations being sent from a tenant. If such anomalies are detected, the tenant may be temporarily blocked.

To unblock your tenant, please provide a business justification explaining the need for bulk invitations along with requested details via private message only (do not post publicly).

1 answer

Your answer

Anonymous

2026-04-22T15:12:43.9866667+00:00

Since it is a new tenant, not the core one, we don't have a Microsoft priority support, so we are stuck to posting this issue here.
Thanmayi Godithi 11,905 Reputation points Microsoft External Staff Moderator

2026-04-22T15:50:40.7033333+00:00

Hi Klaudio, Thank you for reaching out to Microsoft Q&A.

As part of its security enhancements, Microsoft has anomaly detection systems in place to identify unusual activity, such as an unusually high number of invitations being sent from a tenant. If such anomalies are detected, the tenant may be temporarily blocked.

To unblock your tenant, please provide a business justification explaining the need for bulk invitations along with requested details via private message only (do not post publicly).

Answer 1

The described behavior indicates that the tenant is being restricted by Microsoft platform-side protections and not by any configurable Entra ID policy or role setting inside the tenant. This type of restriction cannot be removed through portal configuration, Terraform changes, or standard admin actions, even with Global Administrator permissions.

To proceed, the only supported path is to engage Microsoft support so the tenant can be reviewed and, if appropriate, unblocked or adjusted by Microsoft.

Use one of these approaches:

Open a support case from an accessible tenant
- Sign in to the Microsoft 365 or Azure portal with an account that has support entitlement (for example, an existing production tenant).
- Create a support ticket describing:
  - The affected tenant ID and primary domain.
  - That it is a newly created tenant for a hackathon/PoC.
  - That external guest invitations are being blocked despite no conflicting policies and Global Admin rights.
- Ask specifically for the case to be routed to the appropriate Microsoft back-end/support team to review tenant-level restrictions on external collaboration/guest invitations.
Use the phone-based support path
- Call Microsoft’s global customer service/support phone number for the region.
- Clearly state that:
  - This is a commercial/organization tenant.
  - The caller is a Global Administrator.
  - The issue is that the new tenant appears to be restricted from inviting external guest users.
- Request that a support ticket be opened and escalated to the team that can review tenant-level restrictions.
If no existing tenant has support, create a temporary trial tenant to open a ticket
- Create a new Microsoft 365 or Azure trial tenant (separate from the blocked one).
- From that trial tenant’s admin center, open a support ticket on behalf of the affected tenant, providing its tenant ID and details.
- Clarify in the ticket that the trial tenant is only being used to reach support and that the actual problem is with the other tenant.

Key points:

Internal configuration (guest policies, admin roles, administrative units) is not sufficient to resolve a platform-imposed restriction.
Only Microsoft support and back-end operations can review and adjust such restrictions.
Because this is time-sensitive (hackathon), use phone support plus a portal ticket to accelerate routing to the correct team.

References: