Gasteinladungen aufgrund verdächtiger Aktivitäten blockiert – es können keine externen Benutzer hinzugefügt werden

I noticed that you posted your question in English, so I’ll continue communicating in English for clarity. However, if you would prefer to switch to German (de-DE), please feel free to let me know and I’ll be happy to accommodate. 

Hello Mark Kovacs,

Thank you for providing the detailed information.

Based on the error message, guest invitations appear to have been blocked at the tenant level after Microsoft’s security systems detected activity considered potentially suspicious. This restriction cannot be removed through the SharePoint or Microsoft Entra admin settings, even when the external sharing and guest invitation configurations are correct. Microsoft Support will need to review the affected tenant and determine whether the restriction can be removed.

Please sign in to the Microsoft 365 Admin Center using an administrator account and select Help & Support.

Then you can type "I need agent support via phone or email" and click on "Contact support". From there, you can choose your preferred support method, such as phone or email, and request that the case be reviewed by the appropriate team for further assistance. You can mention that Microsoft Entra B2B guest invitations are blocked due to suspicious activity and that you need the tenant-level restriction to be reviewed.

When opening a support ticket, please make sure the Support Assistant (AI) in the Help panel is turned Off. Several customers have reported that the Contact Support option may not appear while the Support Assistant is enabled. Once the AI assistant is turned off, you should be able to enter a description of the issue and the Contact Support option will appear, allowing you to submit a ticket directly to Microsoft Support. 

Alternatively, you may contact Microsoft Support by phone using the regional support numbers listed here: Contact Microsoft customer support | Microsoft Support 

When you call the support number, you may first hear a recorded introduction for approximately 30 seconds mentioning online support resources. You can simply wait for the menu options to begin. Then select "1" as a business email user and "1" again for technical support. This should help route your call to the appropriate support team more quickly. 

Please note that only Microsoft Support can investigate and potentially remove this service-side restriction. There is no administrator setting, SharePoint configuration, or PowerShell command that can manually override the block from within the tenant.

I hope this helps point you in the right direction. If you encounter any difficulty opening the support ticket through the Admin Center, please let me know what happens, and I’ll be happy to provide further guidance.

Kind regards,

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