Can you post a screenshot of the error? Did you look at the server logs?
The fastest way to fix is to do a clean restart of the application.
It sounds like the SOLR search index service is down. Do views and browsing around the interface still work like normal?
What is the output of the command: tabadmin status -v
This will tell you if there are other problems. How to Use tabadmin
As Vikram said, the easiset way to recover would be to restart by using tabadmin restart.
The logs may indicate where the problem came from. Has this issue happened before? How long was Tableau running before the issue occurred? If the issue happens again after a restart, contact firstname.lastname@example.org for help and someone will answer your support case.
Our Prod server on 9.3.0 is showing that
"That page could not be accessed.
The Search & Browser Server is down."
but tabadmin status -v shows its running.
Even though the command line said it was running but GUI said it was not -we restarted tableau services and its been good for the past 12 hrs.