Check the posting date.

When I look at the General Ledger Detail Report, it shows 7/31/2019 for Date, it shows the Posted Date as 9/20/19 for the Debit and 9/23/19 for the Credit  When I attempt to run the Trial Balance, I run it for the entire 2019 year, but it does not show at all.

Each transaction has one Posting Date.

Is fiscal year aligned with calendar year?  The entries won't show up if the 2019 fiscal year ends before the transactions were posted.

I am sorry, but I think I have found the problem.  It appears that the entry that appeared to the client to be missing, was just one debit and one credit line from a much larger Journal Entry.  She was expecting these two lines to appear as separate journal entries on her Trial Balance and Financial Statements, but it actually is showing the whole thing.