Encoder connection from closed loop to semi-closed loop

Hi,

We have a 0M controller that has a separate linear encoder along with the motor encoder. It happens to be the 2nd axis, so it goes on M38 and M39 of the axis control card. The linear encoder gives position feedback (M38) and the motor encoder (m39) gives the speed feedback. We have issues with the linear encoder as it skips pulses, so we want to make a semi-closed loop connection and only use the motor encoder. I disconnected the linear scale and connected the motor encoder to M38 instead. I also changed parameter 37#1 to 0.

What I get is a 400 overload alarm as soon as I start up my machine. Anybody knows what else am I missing? I checked the connection to the encoder already and they are all connected. From what I see from the connection, the only difference between what is used in closed and semi-closed loop for the cable of the motor encoder is PCZn and PCZn*, but all 14 pins are actually connected.

Thanks in advance.

Edit:
Also, just as a detail, this 400 overload alarm disappears if I connect it back to closed loop.

Edit:
(Even weirder, the overload alarm disappears once I connect the linear encoder to M39 even though it is deactivated)

Edit:
And that last edit solved the issue, now only have to adjust parameters 8284, 8285, 8223 and 8224.

Cheers all.