I have a problem with changing tools in a DMC 50V from -96 with a Grundig Dialog 112 controll

The machine has been used in production but only with one mill and therefore not using the tool changer for over ten years, last week we had a service engineer from DMG Scandinavia here for a check on the machine, and when he tried to change tool the machine "locked" itself.

There is in the manual a procedure how to run the machine free from the tool changer if there is a malfunction, but I got no response or movement with this procedure.

Do anyone perhaps have any idea on how to solve this problem?