Overview

You are trying to find a particular document using the search functionality, but the results are not expected. The search required the use of the whole term to find the document successfully. For example, to find the document "El Rates," using "rates" would not be sufficient. You added Metadata tags and verified the document titles were correct; however, these attempts did not resolve the situation.  

Solution

This behavior can be seen when using the "Document Portal" result source, which has more restrictions in the search query. You can instead make use of the "Documents" result source within the Document Portal Web Part to provide less restrictive search functionality.

1. Go to the site in question and click Edit Page under the Gear. 
2. Edit the Document Portal Web Part. 
3. Set the result source to "Documents." 
• To see what result sources are available, click the Gear > Click Site Settings. Click Search Result Sources under Site Collection Administration. You may have to navigate to the top-level if you do not see these menu items.
• The result sources are assigned to a web part simply by typing the name of the result source in the web part field for the Result source. You may also open the result sources and click the Test Query button to see how each reacts to your search queries.