[Q] Email search not working topic

Whenever I search for something in the search bar of the email app, it insists that the word for which I am searching does not exist in either my device or on the server.

I've tested this numerous times with both my email accounts (Gmail and Outlook) and it won't acknowledge finding anything ever (including, for example, the subject line of the very first email in my account).

Is this a known problem, or am I just unlucky?