Forum Discussion
Azure AD Connect - Synchronization Service Installation fails
mmw_it Sounds like your issue might be due to connectivity to a DC in your network.
System.DirectoryServices.AccountManagement.PrincipalServerDownException: The server was unable to connect. ---> System.DirectoryServices.Protocols.LdapException: The LDAP server is not available.
Is ADDS installed on this server?
Was the server promoted to a DC?
Installing Azure AD Connect on a Domain Controller is not recommended due to security practices and more restrictive settings that can prevent Azure AD Connect from installing correctly.
I suggest going through these prerequisites.
https://docs.microsoft.com/en-us/azure/active-directory/hybrid/how-to-connect-install-prerequisites
rosaliodYes, ADDS is installed on this server and yes, the server was promoted to a DC. This may not be recommended, but it is the most standard case in small businesses (in our case 50 users)?! We have not found and heard anything that others have problems with. Quite the reverse!
The LDAP server is online (checked via telnet localhost / server ip 389 or 636). Naming context is like LDAP://COMPUTERNAME.ad.contoso.com/....
