A lookup definition is correctly configured, but when used in a search, no results are returned. The lookup file exists and contains data. What is the most likely cause?
If case_sensitive_match is set incorrectly (e.g., false when it should be true), mismatches occur.
Why this answer
Case sensitivity mismatch is a common issue: if the lookup definition expects exact case but the search field has different case, no match occurs. Option A is unlikely as too many fields do not prevent matching. Option C, disabling field extraction, would affect other parts but not lookup matching directly.
Option D, format mismatch, would cause an error, not silently return no results.