After a server migration or when the name of a server is change, it will be necessary to update each client's ini file to reflect the change.

On the Client computer, browse to HachWIMS\Client\Hach_WIMS_Client.ini file (usually located on the C drive) and open it in notepad.
Adjust the datasource to the new server and save the file.

Run the Client to make sure it connects.

Users can now start to use Hach WIMS again.