Reason: missing token 'xyz' in CORS header 'Access-Control-Allow-Headers' from CORS preflight channel.Reason: expected 'true' in CORS header 'Access-Control-Allow-Credentials'.Reason: Did not find method in CORS header 'Access-Control-Allow-Methods'.Reason: invalid token 'xyz' in CORS header 'Access-Control-Allow-Methods'.Reason: invalid token 'xyz' in CORS header 'Access-Control-Allow-Headers'.Reason: CORS request external redirect not allowed.Reason: CORS header 'Access-Control-Allow-Origin' does not match 'xyz'.Prior to Firefox 4 and Gecko 2.0, it was possible for extensions and plug-ins to add user agent parts, but that has not been possible since bug 581008. Some Gecko-based browsers may not opt into using this token for this reason, sniffers should be looking for Gecko - not Firefox! firefoxversion will generally represent the equivalent Firefox release corresponding to the given Gecko version. Firefox/firefoxversion is an optional compatibility token that some Gecko-based browsers may choose to incorporate, to achieve maximum compatibility with websites that expect Firefox.For instance, this could be " Camino/2.1.1", or " SeaMonkey/2.7.1". appname/appversion indicates the application name and version.Mozilla/5.0 (platform rv:geckoversion) Gecko/geckotrail appname/appversion Mozilla/5.0 (platform rv:geckoversion) Gecko/geckotrail Firefox/firefoxversion appname/appversion
Note: The recommended way of sniffing for Gecko-based browsers (if you have to sniff for the browser engine instead of using feature detection) is by the presence of the " Gecko" and " rv:" strings, since some other browsers include a " like Gecko" token.įor other products based on Gecko, the string can take one of two forms, where the tokens have the same meaning except those noted below:
Reason: Multiple CORS header 'Access-Control-Allow-Origin' not allowed.
See also this document on user agent sniffing and this Hacks blog post. For a breakdown of changes to the string in Gecko 2.0, see Final User Agent string for Firefox 4 (blog post). Reason: CORS header 'Access-Control-Allow-Origin' does not match 'xyz' This document describes the user agent string used in Firefox 4 and later and applications based on Gecko 2.0 and later.