I am referring to instances when the server performance is really slow or the server just won't allow anyone to log in for various infrastructure or server problems. In place of your usual Business Landing page, has anyone tried to build a proactive "Issue Notification" page that informs their users that the current page/dashboard/s is down or really slow at the moment? It's similar to when a shopping site goes down and it lets its customers know that there is a problem and they're fixing on it, than just getting a "Cannot Display Page" generic notice.
I'm not sure if I am articulating this enough but I hope you get the idea.
I think you are referring to a MOTD (message of the day) feature? It's not a feature in Tableau Server yet. However, you can vote for the idea here: