Error When Adding Users

Hi Experts,

I am trying to add an user into my BPC 10.1 Standard (NW) and I am getting this error:

Error: System Exception.

My BPC is on SP6 and this environment is my QA. I do not have the same issue in DEV and both are into the same SP.

I have tried to solve this issue applying many notes but none of them have solved my problem.

Also, I have tried to add an user into my Environment Shell, but no success.

If anyone got the same issue, pls, let me know!

Thank you