Symptom:

When you click a Proofer Controller or proofer, the system displays a message that says, Client is Out of Sync with the Controller, Versions: Client (1.<X>.<XXX>) Controller (1.<Y>.<YYY>).

Cause:

The proofer software is divided into two main components:

To work correctly, these two must be running the same software version. Because each is upgraded individually, the two can become incompatible because the software versions are out of sync.

You can always connect to a Proofer Controller using Proofer Administrator, even if the client and Proofer Controller software are out of sync, because that is how you upgrade the Proofer Controller software and manage software versions.

Solution:

In the error message, make a note of the versions of the proofer client software and the Proofer Controller software.