When working with Matomo, I notice on some websites that the Firefox console with the network analysis shows that Firefox had blocked the requests to Matomo and a NS_ERROR_FAILURE was happened.
See the screenshot.
However, in the Matomo visitor log I see that the tracking requests arrived and were processed.
I investigated this further.
The Firefox behavior occurs when
a) Matomo is addressed on a subdomain or domain other than that of the website.
b) The web server has set an HTTP header x-xss-protection “1; mode=block”
It seems that FF sends the request to the Matomo server, but does not accept the server response… That’s why the tracking works well anyway…
thank you for your feedback. I see it the same way as you. However, I have found some websites with this setup and am not responsible for it. But I will give the webmasters appropriate information.
As far as I know, there is no XSS issue there, but rather incorrect use of an old HTTP header