The selected service account cannot authenticate with the replica source %3:%4 using Kerberos mutual authentication. The ...

The selected service account cannot authenticate with the replica source %3:%4 using Kerberos mutual authentication. The service account for the new Active Directory Domain Services replica should be a domain account trusted by the forest. Also, verify that the replica source has a properly registered service principal name (SPN). 
The authentication failed with error %1: %2