Site broken in Firefox? Check Enhanced Tracking Protection

Firefox’s Enhanced Tracking Protection (ETP) blocks known trackers and keeps each site’s cookies in a separate jar. It’s gentle in Standard mode, but Strict mode and cookie restrictions can break sign-ins, embedded videos and payment pop-ups.

Updated November 2026. Menus move around between versions: if a label is a little different, look for the closest match.

Signs it’s Tracking Protection

A sign-in pop-up that closes and leaves you signed out, or a “please enable cookies” message.
Embedded videos, social posts or comment widgets that stay empty.
The page works in a private window of another browser, or in Firefox with ETP set to Standard.
It only breaks in Firefox private windows (in Standard mode, ETP blocks tracking content only there).

Quick test: is it ETP?

Click the shield icon at the left of the address bar.
Switch Enhanced Tracking Protection off for this site. Firefox reloads the page.
If it now works, ETP was the cause. You can leave it off for just this site, or switch it back on and try the narrower fixes below.

See exactly what ETP blocked

Open the shield panel again. It lists the categories blocked on this page: social media trackers, cross-site tracking cookies, tracking content, fingerprinters, cryptominers.
Select a category to see the domains in it.
Tracking content (embedded players, widgets) and cross-site cookies are the categories that break things most often.

Fix it without losing protection everywhere

Keep it off for this site only: the per-site switch is remembered. Your list of exceptions is in Settings → Privacy & Security → Manage Exceptions.
Strict mode breaking too much? Switch to Standard in Settings → Privacy & Security. Standard still blocks social trackers, cross-site cookies, cryptominers and known fingerprinters, and blocks tracking content in private windows.
Sign-in problems: Firefox may ask “Allow site to use cookies on other site?” during a sign-in. Allow it; that’s the narrow fix for cookie isolation.
Report it: the shield panel has an option to report a broken site to Mozilla, which helps them fix it for everyone.

Good to know

ETP checks requests after your extensions. If uBlock Origin or Privacy Badger already blocked a tracker, ETP never sees it, so it can look like ETP did nothing.
ETP can break things without blocking any request at all, by restricting cookies and storage. Look at the cookie categories, not just the blocked list.
Firefox sometimes swaps a blocked script for a harmless stand-in (SmartBlock) so pages keep working. That’s why some blocked trackers don’t break anything.

Let Why Block find it for you

Firefox reports ETP blocks with its own error codes, so Why Block can say with high confidence when ETP is the cause, separately from your extensions.

Blocked trackers are labelled “Firefox Tracking Protection”, and trackers that loaded with restricted cookies are listed separately, since those break sign-ins without showing up as blocks.
Firefox doesn’t let one add-on switch others off, so the automatic test isn’t available there. Use Manual compare in the report: switch one blocker off yourself, reload, and Why Block shows exactly what changed.
The impact rating at the top says what the blocking actually broke (sign-in, video, comments, payments, images, the whole page) and what was blocked as intended (ads, analytics, tracking pixels).