When the navigation item is saved with special characters, the user is unable to open the form. It throws an error message "Due to either a session timeout or unauthorized access. You do not have permission to access this page".
Upon clicking a navigation item, an error is reported:
Due to either a session timeout or unauthorzed access, you do not have permission to access this page.
When you create a custom navigational link, if special characters are used such as /, \, &, #, %, they break the capability to redirect the user to a form or to an external link.
Resolving The Problem
When you build a custom navigational link, refrain from adding a Special Character (/, \, &, #, % ). They must be omitted so that the form renders when clicked.
See APAR IV84655: NAVIGATION LINKS FAIL TO LOAD WHEN SPECIAL CHARACTERS ARE REFERENCED
17 June 2018