If you are upgrading from version 13 and you previously used linking to objects within the Unity Viewer, upon upgrading, the links will no longer function due to the addition of security signatures in links. If you want to make links created in version 13 to function, you must add the following setting in the Application Server's web.config file under <appSettings>:
<add key="permitUpopLinksWithoutSignatures" value="true"/>
This setting should only be used temporarily. Once enough time has passed where links are considered "expired", this setting should be removed.