If it works with the -n or --nopbo option that clearly points to the OpenGL interop as root cause for the failure.
Maybe add code to the OptiX example to print out all information about the OpenGL implementation you can query with glGetString:
[url]https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/glGetString.xhtml[/url]
If that is not showing an NVIDIA OpenGL implementation, then that would be one problem.
Other than that I do not know how remote rendering works exactly under Linux and what is sent to the client. If the client is gettting the OpenGL calls for indirect rendering, the OptiX server side (CUDA) would also not be able to interop with that.
Not using OpenGL interop might probably the only working solution for remote rendering then.