Firefox Community Forum

I am running Firefox version 153.0.1 on a 64bit install of Windows 11.

A few days ago I had to factory reset my computer, including a clean Windows install. Since then, when attempting to access https://vodafone.cz/muj/prihlaseni, I get an Imperva Error 15 "Access Denied" error screen - screenshot attached here. Clicking the Imperva logo on the bottom of the error message leads to https://www.imperva.com/why-am-i-seeing-this-page/?src=23.

I was able to access the site in the past, most recently on July 8, 2026 - this would have been Firefox version 152.0.5.

This error persists in troubleshooting mode but not in private/anonymous (with or without extensions enabled), nor does it appear in Microsoft Edge or Firefox on Adroid.

Clearing cookies and cache did not help - in fact the error first showed up on a clean install of Firefox, when there weren't any cookies or cache stored yet. I've tried different DNS over HTTPS settings and listing the site as an exception in settings, but none of this made a difference. Enabling Firefox's built in VPN also made no difference, regardless of the selected location.

I found a recent post (https://support.mozilla.org/en-US/questions/1588627) describing a similar issue on a different website and tried the suggestion listed there to try a fresh profile - this seemed to work, but within a couple of minutes of browsing the error message returned. I've even reinstalled Firefox entirely, but this too did not help for long.

Interestingly enough, the error message lists a proxy IP address (not blacked out on the screenshot) despite the fact that I am not using a proxy.

The website provider's tech support claims this is an issue on the user side, not theirs - they have not been able to replicate the issue.

Is there anything I'm missing that would explain why this is happening?

Thanks!

Chaque fois que je lance une recherche sur Qwant avec Firefox j'ai le message: "Qwant.com est temporairement indisponible" alors que ça fonctionne avec Safari une idée ? [redacted email]

Ich habe einen DEepl Pro Account. Mein Standardbrowser ist Firefox. Ich melde mich im Firefox-Browser für die Desktop-App an. Es erscheint der Hinweis: "Du hast dich erfolgreich angemeldet und wirst gleich zur App weitergeleitet." Die Weiterleitung scheint von Firefox blockiert zu werden (wozu eigentlich???). In den Einstellungen ist meine Präferenz für Deepl.com korrekt aktiviert. Ich möchte Firefox als Standardbrowser nicht aufgeben, doch das scheint die einzige bekannte Lösung zu sein, die sofort hilft. Ich nutze an einem PC mit Windows 11.

Meine Frage: Wo kommt dieser Bug her und wie muss ich Firefox genau einstellen, damit solche Blockaden nicht passieren?

(Ich beobachte solche dummen, unerwünschten Blockaden in Firefox leider häufig, nehme dann manchmal den Link und öffne ihn einfach in Chrome, was immer problemlos möglich ist. Ich möchte nicht die Funktionalität des Browsers mit endlos vielen "Sicherheitseinstellungen" erwürgen.)

I asked AI: "I'm being prevented from using options which cause pop ups but I don't think I've deliberately changed any settings. I want to use "analyze the board" on the Gameknot website but I'm being prevented from using it. How can I get it back?" I followed the instructions: "Mozilla Firefox: Click the three lines (top right) > Settings > Privacy & Security > Permissions. Go to the "Pop-up windows" section and click Exceptions, then add https://gameknot.com" but I haven't re-acquired use of the pop up I ant to continue working. I want it back and its extremely irritating as the work around is very long and boring.