Fix a Firefox sign-in loop without abandoning Total Cookie Protection

Total Cookie Protection partitions third-party cookies by the site you are visiting so the same embedded service cannot easily track you across unrelated websites. Mozilla says it is enabled by default for Firefox users. Some sign-in flows expect third-party storage to work differently and can loop back to a logged-out screen. That symptom has many other causes, so test before changing a privacy control. A site-specific fix is preferable to a global reduction.

Before you start​

Make sure the address is the real service and Firefox is updated. Note whether the failure occurs in a private window, a normal window or both. Do not clear all browser cookies as a first move; that can sign you out everywhere without identifying the culprit.

Do it step by step​

1. Reproduce the exact login loop and note the page where it returns to signed-out status. Check the service's own status page for an outage.
2. Click Firefox's shield for that site and temporarily turn Enhanced Tracking Protection off, then reload and try the same login. If it still fails, restore the shield; Total Cookie Protection may not be the cause.
3. If disabling the shield fixes the issue, inspect Firefox's web-compatibility settings and try a built-in exception appropriate to your protection level. Do not change about:config based on a random troubleshooting post.
4. Use a site-specific exception only for the verified service and only while needed. Finish the workflow, then test whether you can re-enable the shield without recreating the loop.
5. If the failure persists under different settings, clear data for only that site, test extensions in a controlled way and contact the service with a reproducible description. Avoid broad global cookie changes unless you understand their tracking cost.
6. Review saved protection exceptions later. A once-broken site can be fixed by its operator or Firefox, so an old exception need not remain forever.

Check the result​

The sign-in succeeds and the rest of Firefox retains its normal tracking protection. You have evidence that changing a specific setting caused the difference, or you restored it when it did not help.

If something goes wrong​

If a private window behaves differently, that can reflect other cookie and extension behavior. Compare carefully without assuming the result proves one mechanism. If the site requires third-party cookies globally, ask its operator for a supported alternative.

Know the limit​

Partitioning limits one tracking technique, not all fingerprinting or account-based profiling. Disabling ETP for a site may allow trackers there. The cause of a sign-in loop must be demonstrated rather than guessed from the presence of Total Cookie Protection. Mozilla Total Cookie Protection breakage