Abs MT 20 Bit Encoder Losing Position after power off on

Hello,

Servo motor model is 1FL6064-1AC61-2LA1 and driver 6SL3210-5FE11-5UF0.

mechanical bond rate is 1/193.5675 and pitch 4 mm.

When ı after making a reference, when I enter the HARDWARE LIMIT after 60 mm and turn the machine off and on, motor forget the encoder position. I changed servo motor,encoder cable and driver but still same problem.