SP9021 (S1) POS Sensor polarity error

Hello everyone

We purchased a used Doosan lynx 300.
We finally hooked everything up and started the first program.

We are recieving the following error and then the machine stop:

SP9021 (S1) POS Sensor polarity error

I searched and found out that it has to do something with parameter setting No. 4000#0, 4001#4.

I would appreciate if someone could help.

Thanks.