Do the following as OTRS administrator:

1. In the OTRS dashboard, select the Admin tab.
2. In the Admin tab, select SysConfig in the "System Administrattion" section.
   
   The "SysConfig" dialog appears.
   
3. In the "Actions" section, search for Frontend.
   
   The search results are displayed on the right.
   
4. Select Frontend::Agent::Ticket::ViewZoom in the list of search results.
   The
5. If needed, enter the correct URL then click Submit.