--- a/testing/firefox-ui/tests/functional/security/test_safe_browsing_initial_download.py
+++ b/testing/firefox-ui/tests/functional/security/test_safe_browsing_initial_download.py
@@ -27,16 +27,17 @@ class TestSafeBrowsingInitialDownload(Fi
 
     prefs_provider_update_time = {
         # Force an immediate download of the safebrowsing files
         'browser.safebrowsing.provider.google.nextupdatetime': 1,
         'browser.safebrowsing.provider.mozilla.nextupdatetime': 1,
     }
 
     prefs_safebrowsing = {
+        'browser.safebrowsing.debug': True,
         'browser.safebrowsing.blockedURIs.enabled': True,
         'browser.safebrowsing.downloads.enabled': True,
         'browser.safebrowsing.phishing.enabled': True,
         'browser.safebrowsing.malware.enabled': True,
         'privacy.trackingprotection.enabled': True,
         'privacy.trackingprotection.pbmode.enabled': True,
     }