Try to delete session credentials file if exist and acquire cred again with blcred. It should solve your problem.
Whenever you see this issues. Please check the following things
1. Session credentials are valid. So as suggested by Vijay would defintely help
2. Another thing to check is if the role has the NSHProxy.connect authorization
3. Check the nsh application server logs if you have access to see the reason behind the failures
Make sure your Exports, Users and Users.Local is also updated with the right info and mapped to Local Admin.
Thanks everyone for the suggestions. I did a little looking around and it turns out the error is coming out of my win desktop's NSH executable.
I previously had another NSH version and Console installed (version 8.5.1), and then installed version 8.6 console and NSH alongside the 8.5.1 version (we have multiple Blade environments and not all environments are at same version so I had to maintain 2 versions of the console and NSH)
When ran cmd, then NSH, it tried to connect to 8.5.1 NSH shell and tried to proxy that to an 8.6 appserver, which resulted in the errors. When I tried running an 8.6 NSH executable directly and ran a proxy command from there, it works w/o issues.
So the lesson is, if you have multiple versions of Blade consoles and NSH shells installed, update your PATH and env vars when running it from CMD prompt. This is the reason why my Linux NSH client works w/o issues but win desktop has these errors
if you launch it from the start menu it will call the NSH\bin\nsh.bat and set the env vars properly.