When previewing a query you are able to choose which columns appear on the screen. If you remove all journal entry columns, such as Date, Received, or Type, and only keep account columns, such as Account Name or Email, you will encounter an Application Error.
If you change the data return type of your query to Accounts, you will be able to run the query preview without error.
We are currently evaluating this issue and will update this article when we have more information.
Steps to Duplicate
Preview any query set to return Journal Entries
Click Choose columns and remove any journal entry column and leave all account based columns