User Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:57.0) Gecko/20100101 Firefox/57.0 Build ID: 20170925150345 Steps to reproduce: Sometimes Firefox (Developer Edition 57.0b3 x64) does not load Favicon for sites (in most cases on Google sites, but not only). The problem is reproduced on several of my working computers. Actual results: Favicon on the page tab is not displayed

More screenshots https://de-v.net/v/2017-10-03_13-06-14.png https://de-v.net/v/2017-10-03_13-06-47.png https://de-v.net/v/2017-10-03_13-07-01.png

Not fixed in 57.0b5 https://de-v.net/v/2017-10-04_10-45-18.png No favicon on Facebook Messenger, Google Search and Google Translate.

Could you try it again with a new profile please? I couldn't reproduce it with 57.0b5, see the attached picture.

Is the icon never shown, or sometimes it's shown, sometimes it's not? If the latter, this is likely a dupe of bug 1403963. What's the EXACT url of the pages where you can reproduce this?

I could reproduce a delay on google translate, where the icon was not shown until I clicked on the tab. Do you see something similar? Since this is an ico file, it could be somehow related to bug 1401122. another interesting experiment may be for you to check in the Web Console whether you see the request to translate.google.com/favicon.ico. There could even be something in the middle (antivirus?) touching the secure connections...

I said the Web Console, but likely the request would be visible in the Browser Toolbox under Network, after enabling Chrome debugging in devtools options.

I'll reproduce my problem and record it https://de-v.net/v/2017-10-04_22-31-34.webm First tab (pinned) - Gmail

And reproduce with empty cache/coockies/history/etc - https://de-v.net/v/2017-10-04_22-37-34.webm

But i can't reproduce problem, when no any pinned tabs open when i run Firefox. No any firewall installed (except Windows Firewall), legal copy of Windows 8.1 with latest updates, no restrictions at the country or provider level for access to these sites. The problem is also repeated on the office computer located inside the network of another ISP.

Could you please inspect the tab using the Browser Toolbox and check it properly has an image attribute pointing to the favicon? Could you also check if the image appears in your cache (about:cache should help) and what's its data size?

Inspecting of this window https://de-v.net/v/2017-10-05_19-49-52.png looks like => https://de-v.net/v/2017-10-05_19-50-26.png Red underline - tabs without favicon, green - everything ok.

Strange, but I can not find icons that are underlined in red in "disk storage" https://de-v.net/v/2017-10-05_19-56-49.png But the icons underlined in green are on the list.

There are some Try builds here that are solving another bug with icons, I don't know if there's any relation, but it may be interesting to try them and see if they help with the problem: https://bugzilla.mozilla.org/show_bug.cgi?id=1401122#c23 (direct link https://treeherder.mozilla.org/#/jobs?repo=try&revision=ade5a8bf5f8ca53a4f59086334a7c8d5f7a09dae) Just click on the B and look for the target.zip file. you can create a link to the .exe and add --no-remote --profilemanager to the link, so you can test these on a separate profile. These are nightly based, I think.

After two days of using the test build, I didn't see any problems with favicon

Thank you, let's set a dependency for now.

a Network problem has been fixed in Nightly and Firefox 57b8 (bug 1401538), please check if you can still reproduce on one of those.

Okay, i'll try to reproduce in the next one-two days and report the results.

After a long test on several working computers, I was unable to reproduce the problem. Apparently, the problem is solved (tested on 57.0b8 and 57.0b9).

Ok, let's assume it's a dupe then.

And thank you for helping with this!