The Symptom
While monitoring certificates issued through Microsoft Intune's cloud PKI, administrators might encounter failures leading to unexpected certificate issuance terminations. The error is encountered in the Intune portal under the Certificates section, reading:
Error: Certificate issuance failed due to unexpected termination at the CA server...
Root Cause
The root cause of this issue is often related to communication failures between the Intune service and the Certificate Authority (CA) server. Specific causes include:
- Misconfigured NDES settings: If the Network Device Enrollment Service (NDES) settings are incorrect, certificate requests might be routed improperly.
- Expired NDES credentials: Service account credentials in Intune that are expired or not updated can cause disruptions.
- Network restrictions: Firewalls or network policies that block communication between Intune and on-premise or cloud-based CA servers can lead to authentication failures.
SCEP protocol disruptions can halt the process, causing the error message to appear in Intune.
Diagnose
Confirm the root cause using the following PowerShell script to check NDES service status and validity of configurations:
Get-Service | Where-Object { $_.DisplayName -like '*NDES*' }
Additionally, ensure no network/firewall restrictions are present by testing connectivity:
Test-NetConnection -ComputerName CAserver -Port 443
The Fix
To resolve the error, execute these steps:
Verify NDES Configuration
Navigate to Intune Admin Center > Devices > Configuration profiles > Choose a profile > Properties and validate NDES settings to ensure they are correct.
Update NDES Service Account Credentials
Update expired service account credentials. Ensure these credentials have the necessary permissions on the NDES server.
Check Network Configuration
Ensure no network restrictions are blocking Intune from communicating with the CA server.
Renew CA Certificates
If CA root certificates are expired, renew them following Microsoft documentation.
Verification: Attempt to issue a new certificate and verify its successful issuance in the Intune Admin Center.
Prevention
Implement these proactive measures:
Regular Credential Updates
Create a policy to review and update expiring credentials for NDES services.
Monitor Certificate Expiry
Use Intune compliance policies combined with Azure Monitor alerts to notify admins ahead of certificate expirations or service failures.
Connect-MgGraph -Scopes "DeviceManagementConfiguration.Read.All" # Implement further PowerShell or Graph API calls for continuous monitoring.
Ensure Robust Communication
Regularly audit firewall and network settings to ensure consistent communication between Intune and CA servers.
Proper monitoring and maintenance of your Intune configurations will significantly reduce the likelihood of encountering certificate monitoring failures and bolster your organization's security posture.
