If your Gmail Search Not Working, it's because your system is unable to establish a reliable internet connection. It's also possible that the Gmail Sync settings on your phone aren't turned on. This issue is also caused by an outdated version of the Gmail software on your smartphone. So, when you don't upgrade your Gmail app, you may experience this error. Alternatively, if you repeatedly use the same windows to access Gmail, a misconfigured cache is created, & this problem occurs.