3822225 - Error 500: The server encountered an error and could not complete your request.(Updating Login ID/ Employee ID)

I manually enter a new Login ID or Employee ID for a User within their User Administration Profile, but when I click save it gives an error message.

When I am trying to update the User's Login ID or Employee ID in their User Profile I get the following error message. Sorry, something went wrong. The server encountered an error and could not complete your request. If you continue to experience problems, please contact your Company Administrator or Help Desk. (Error 500) , KBA , CON-CA , Cross Applications , CON-CA-ADM , Administration , Problem