Incorrect parameter setting:
TrfErrEna was set to ON and should be OFF
Check TrfErrEna Circuit:
Check for 24V supply from customer PLC or transformer signal at X751. If it isn't present, check for fault outside of the inverter. If present, check light on the small green relay K25. Remove/replace cartridge. Check that signal is passed through the contacts and is arriving at the SC20cont X11 pin 10.
Occasionally, you can offer to jumper 24V to energize the K25 relay and bypass the customer's supply. Or simply turn off the parameter.