If you are wondering after setting up the query suggestion in SharePoint 2013 Server, you might feel like suggestions are not coming up after six times??!! ..Gotcha..
This is due to the scheduled timer job "Prepare Query suggestions". Run the timer job manually in your SharePoint environment as a site collection admin.
The commands are as follows.
Start-SPTimerJob -Identity "prepare query suggestions"
This solution is not applicable for SharePoint online environment. you have to wait for scheduled job to run