Lenze PL trip

Hi
We have a Lenze positioning control 93xx / software version 7 Global drive EVS9326-EP with a 10 KW MCS servo motor utilizing a SRS50 SICK encoder. X8 is the port that is dedicated to HIPERFACE encoders.
Some circumstances force us to do a rotor position adjustment with the via GDC software (Global Drive Control software). After That We can not eliminate PL trip.

If the rotor position adjustment was completed with an "Sd7" or "PL - TRIP" error (? 9.3?1) it was not possible to assign the rotor position to the feedback system.
Protective measures:
Repeat rotor position adjustment.
Check the wiring and the interference immunity of the encoder at X8.

In order to do a second rotor position adjustment, We should eliminate the PL trip, but the trip persist even after load default parameters. (When we load default parameters in these servo drives, just after setting the motor type or feedback type in C0025, the PL trip returns).
We even can not clear fault history buffer, don't know why, just can not be cleared in diagnostic dialogue.

According to the manual Global Drive System manual, the PL trip is saved with mains failure protection. And mains failure seemingly means failure in power.
We are using 3 phase AC power, and there is no loss in power.
The manual suggests some ways to reset a mains failure trip, like addressing a digital input to MFAIL-RESET High, or via C0972.
Our drive have not C0972 in Code list parameters, and no MFAIL-RESET definition in digital input is there.

In short, how can eliminate PL trip in LENZE EVS 93xx?

Best Regards