If you have the query about Outlook web search not working, then you should firstly check Outlook Index Locations. You should be double sure that Outlook is on the list of indexed locations. For this, open Outlook and go to file > options > search > indexing options. Choose to modify from the Indexing Options panel. Ensure to check alongside Microsoft Outlook and then tap to OK. If still, you are facing an issue, then you need to reinstall Outlook. You can uninstall Outlook and then reinstall it. This will definitely help to get rid of the issue.