Heidenhain 150 B ref.point

When i shell get the reference points on each axis. The machine takes the Z axis to the ref.point and its alright, But when it is going to take the Y axis ref.point it goes there but then stands still on the ref.point and he dont go to the last axis.On the screen it stands Y axis go to ref.point. We have checked the taco and the engine for the Y axis and its alright pluss all the servos are replaced with new ones. When the Y axis goes over the ref point. we have measured that he sends a signal to the Heidenhain 150 B j5/10 Reference end posisition Y. The machine is Abene VHF-3 CNC. Heidenhain TNC 150B

The machine was working perfect the day before and the next day when we start it up it gave us this message.

What can it be for problem when it does not continue to the next axis?