In my recent assignment, I was configuring new Azure AD Connect Server and helping the customer to decommission the older one. However, while configuring the Azure AD Connect Server, we encountered below error:
Azure Service Connectivity failed, Unable to Procced:
The on-premises synchronization service is not able to connect to the Azure Active Directory, Updating the proxy settings for the AD sync account may resolve this issue.
To resolve this issue, please follow below steps:
1: Verify proxy connectivity
2: Check Proxy Settings in Internet Explorer
3: Modify the Machine.config file as suggested in below URL
Once you modify these file. Please reboot your server once.