Issues such as Outlook web app search not working are very common, but at the same time, you can troubleshoot it by following the steps mentioned. Proceed to settings and then click on password and accounts. Now, choose to set Outlook account and choose mail days to sync. Choose no limit, and all your emails will start to sync in some time. If you face Outlook web app search not working issue again, then try to reset the networking settings on the device. Click to settings > general. After that, scroll down the page and click on the reset button. Lastly, choose the reset network settings and then enter the password to confirm the settings.