Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

Die Funktionalität dieser Website ist durch Wartungsarbeiten eingeschränkt, die Ihr Erlebnis verbessern sollen. Wenn ein Artikel Ihr Problem nicht löst und Sie eine Frage stellen möchten, können Sie unsere Gemeinschaft über @FirefoxSupport auf Twitter, /r/firefox oder Reddit fragen.

Avatar for Username

Hilfe durchsuchen

Vorsicht vor Support-Betrug: Wir fordern Sie niemals auf, eine Telefonnummer anzurufen, eine SMS an eine Telefonnummer zu senden oder persönliche Daten preiszugeben. Bitte melden Sie verdächtige Aktivitäten über die Funktion „Missbrauch melden“.

Weitere Informationen

Dieses Thema wurde archiviert. Bitte stellen Sie eine neue Frage, wenn Sie Hilfe benötigen.

CORS error in Firefox incognito mode only

Amit Kumar Singh
Amit Kumar Singh
more options

Hi there, I am working on a site with Segment API and need to load their JS on my site for it to work. Whats happening is, I get the following error: "Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://api.segment.io/v1/p. (Reason: CORS request did not succeed). Status code: (null)."

The weird part is, it happens only in Firefox incognito mode. It works on Chrome, Edge, Opera.

I am wondering if this is by design or if it is a bug.

Firefox version 98.0 (64-bit).

Hi there, I am working on a site with Segment API and need to load their JS on my site for it to work. Whats happening is, I get the following error: "Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://api.segment.io/v1/p. (Reason: CORS request did not succeed). Status code: (null)." The weird part is, it happens only in Firefox incognito mode. It works on Chrome, Edge, Opera. I am wondering if this is by design or if it is a bug. Firefox version 98.0 (64-bit).

Ausgewählte Lösung

Is it a background request (fetch or XMLHttpRequest), or a regular script tag?

CORS background requests definitely require an Origin header. I wonder whether that is suppressed in private windows with some requests? You could inspect the headers in the Network panel of the Dev Tools. More info on that panel: https://developer.mozilla.org/docs/Tools/Network_Monitor

If it's a regular script tag, this could be due to Tracking Protection (by default, stricter in private windows) or an add-on that blocks analytics scripts. For Tracking Protection, click the shield icon at the left end of the address bar to check what is being blocked. With add-on blockers, the UI varies, but the toolbar button usually gives you an info panel.

Diese Antwort im Kontext lesen 👍 0

Alle Antworten (2)

jscher2000 - Support Volunteer
jscher2000 - Support Volunteer
  • Top 25 Contributor
more options

Ausgewählte Lösung

Is it a background request (fetch or XMLHttpRequest), or a regular script tag?

CORS background requests definitely require an Origin header. I wonder whether that is suppressed in private windows with some requests? You could inspect the headers in the Network panel of the Dev Tools. More info on that panel: https://developer.mozilla.org/docs/Tools/Network_Monitor

If it's a regular script tag, this could be due to Tracking Protection (by default, stricter in private windows) or an add-on that blocks analytics scripts. For Tracking Protection, click the shield icon at the left end of the address bar to check what is being blocked. With add-on blockers, the UI varies, but the toolbar button usually gives you an info panel.

Amit Kumar Singh
Amit Kumar Singh Fragesteller
more options

Hi @jscher2000, thanks for the response.

Disabling the Enhanced Tracking Protection worked.