Indramat TRK-6 PUE error

One of the next steps of my milling machine retrofit is to connect the Indramat TRK-6 motor controller. For those interested here is the manual: www.dropbox.com/s/bwd5420fj3rym4x/indramat_trk6-4u_en.pdf?dl=0

When turning on the power the PUE red LED (h3) lights up and I can't seem to turn on the drive. Both RF and RS are connected to 24V. I can clearly see 230V on each of the phase voltage inputs. I tried connecting small voltage to E1A and E1B inputs, but no move from the spindle, which I think is due to PUE.

There is a following paragraph on the page 15 of the manual:

Phase rnonitoring At the moment of switch-on, a signal is generated via capacitor C18 which ensures that the gate control unit is interlocked. If the sawtooth signal has been generated on circuit board NS 1, cornparator V20 switches to -15V. If all 3 cornparator signais are present on board NS 1, transistor T17 (on NS 1) switches input 7 to Zero volts. If this state is rnaintained for rnore than 20 ms, the signal at C18 becomes Zero and the trigger interlock is cancelled. This ensures that the trigger interlock is not rernoved if onephase fails (periodic fault at mains frequency). Red larnp h3 "PUE" indicates that the phase rnonitor circuit has been activated. Note: Phase balance between the synchronizing voltage and the voltage across the load is not monitored

I don't fully understand what it means. Does anyone understand what could cause the phase monitor to turn on?

I think I may have an answer, this is another quote from the manual:

Red lamp h3 "PUE" is off for a clockwise field, if not, 
reverse connecting leads ZU and 2V. Larnp h3 rnust go 
out when the supply voltage is connected. 

I will try to swap some of the wires tomorrow

Yes. That would be the first step.
The drive will not enable if the green BB led doesnt light up.

Just check the other supply to the drive as well. AFAIK there is another supply to the control circuit on the drive. Thhe phase sequence of that must match the main supply to the power stage.

We have the same drive in our Maho.

That was exactly the problem. It also makes sense, because it was working in the past, but at some point the electrical installation was changed. Phases must have been connected differently then.