How do I resolve the error "The Server cannot handle directory requests" during Active Directory Connector installation?

Issue

During installation of the Connector in a Windows Server 2008, Windows Server 2008 R2, or Windows Server 2012 R2 environment, a user may receive the following error after entering the username and password for the OpenDNS_Connector user:

"Exception verifying password: The Server cannot handle directory requests."

Cause

This error indicates that the installer failed to verify the password, which can be due to network or permissions issues. 

Resolution

To resolve or work around this issue, attempt the following steps in order:

1. Ensure that the server on which the Connector is installed is able to reach its DC. Specifically, the Connector needs to be able to bind to LDAP over TCP 389.
2. Attempt to install the Connector specifically as the DOMAIN\Administrator user, even if they are already using a normal Domain Admin account.
3. If installing as DOMAIN\Administrator fails, then ignore the error and continue with the installation. Once the Connector has started, check the logs to ensure that the initial ADSync succeeds, the DC connections work, and that you see a successful QueryADUser for the first few events. If all of that works, there shouldn't be any problems.