PRA is Power Removal Function Active (drive locked out).
It is a state of the drive which means that it is locked. If drive displays PRA, that means that you do not have 24 V on the terminal PWR. Normally, all the drive are delivered with a "link" between terminals PWR and +24.
This situation is for safety reason. When the status of ATV71 is PRA, for safety reason, the software is freezed and nothing is done until PWR and +24 are shunted.
The solution is to shunt PWR and +24 before power on the drive.