Please check this following KB article about the behavior. https://kb.tableau.com/articles/issue/error-not-authorized-errorcode-16-entering-password-in-tabcmd
The common cause is special characters in the password causing the error.
Hope this helps!
Hi Narayana, 1. Can you login with the same URL in cognito mode or private browsing mode? Also try to give port number in the URL.
2. Can you please clarify on what you mean by users don't have local admin access? Do you mean access to server where tabcmd is installed?