Azure Event Grid System Topic Deployment Fails with Maintenance Configuration Source — Anyone Else Experiencing This?

Thanks for reaching out on Microsoft Q&A and really appreciate the detailed troubleshooting steps you’ve already done.

The error typically occurs when Event Grid is unable to validate access to the Maintenance Configuration resource. This can sometimes happen due to role assignment issues, API validation mismatches, or a platform-side regression.

Since you’ve already tested across multiple subscriptions, tenants, and deployment methods (Portal, Bicep, PowerShell), this is unlikely to be a misconfiguration on your side.

To narrow this down further, could you please confirm:

• Region: Which region are the Maintenance Configuration and System Topic deployed in? Does the issue occur across regions?
• Other sources: Are you able to create System Topics successfully from other sources (e.g., Storage Account, Key Vault) in the same subscription?
• Roles: Can you confirm that your identity has the right RBAC roles, such as EventGrid Contributor on the Event Grid resource and proper access to the Maintenance Configuration?
• Template details: Which API version for Microsoft.EventGrid/systemTopics are you using in your Bicep/ARM deployment?

Given that you mentioned these deployments used to work but are now failing consistently, this could point to a regression or backend validation issue on Azure’s side for the Maintenance Configuration event source.

Next steps / Workarounds:

1. Try deploying the System Topic in a different Azure region, as rollouts can sometimes behave differently across regions.
2. Attempt to create the System Topic first without attaching the Event Subscription, then add the subscription separately.
   These above two-step process bypasses the combined validation check that fails, allowing the deployment to succeed.
3. If the issue persists, I recommend raising a support request with Microsoft Support to confirm if this is an active platform issue.

Documentation References:

• System topics in Azure Event Grid
• Azure Event Grid schema for maintenance events
• Authorizing access to Event Grid resources

Hope this helps and thank you for your patience while we looked into this!

Hello Jeroen Monnens, Just checking to see if you have a chance to check my previous response and helped, do let me know if you have any further questions on this. Thank you!

I am also experiencing this. I am trying to subscribe to SMS Events for a POC project, but I get the error
Creation of System Topic has failed with error
Unable to verify access to resource /subscriptions/***/resourceGroups/GWNN/providers/Microsoft.Communication/CommunicationServices/

If I try to create a system topic from the subscription, the UI is not able to read any resources in any resource group so the UI will not pass validation for creating a system topic