Devices Not Enrolling in Intune Despite Correct MDM Configuration

Question

I'm working in a hybrid environment, and all of my devices show up as "Hybrid Azure AD joined" in Azure, which is great. However, the issue is that some devices are successfully enrolling into Intune, while others are not.

I've already verified the following settings but am still unable to get auto-enrollment working:

• MDM authority is set to Intune
• MDM URL is properly configured in Azure AD
• MDM scope is set to "All"
• MAM URL scope is set to "None"
• GPO "Enable Automatic MDM Enrollment using default Azure AD Credentials - Set to User Credentials" is properly applied

Despite these configurations, the Event Viewer shows the following error:

Auto MDM Enroll Get AAD Token: Device Credential (0x0), Resource Url (NULL), Resource Url 2 (NULL), Status (Mobile Device Management (MDM) is not configured.)

Auto MDM Enroll: Device Credential (0x0), Failed (Mobile Device Management (MDM) is not configured.)

Any suggestions on what could be causing this issue or any additional steps I should check?