20200702_ERROR: configuration of piston triangle is not allowed.

1.0.0.121
2019.2.9f1
HI followed tutorial given in below link and trying to learn piston joint.After following all the steps when i configuring piston joints triangle i am getting error  " ERROR: configuration of piston triangle is not  allowed."

can you help me out of this error.

I am not able to open  following support website also.
"V2020.1.56.3_ Feature Overview "
High