Steps to reproduce:

Go to www.youtube.com and start browsing videos. This started to occur after Firefox 100.0 (64 bit) was installed. At 99.0.1 (64 bit) all worked correctly.

Actual results:

Eventually the preview for some of the videos stays grey. After a longer time a screen saying "Your offline. Check your internet connection." is displayed.

Expected results:

The previews should have been resolved and displayed. There is an internet connection.

The Bugbug bot thinks this bug should belong to the 'Core::Networking' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Hi,

Could you try to capture a http log?
If this is easy to reproduce, could you also try to use mozregression to help us find out the root cause?

Thanks.

I have attached a log that I started after the problem began to occur. The problem occurs regularly, but there appears to be more involved to trigger it than I thought. I will keep trying to recreate with logging active from the very start.

Thanks for the log.
This looks like related to 0RTT. Could you try to go to about:config and set security.tls.enable_0rtt_data to false and try again?
It'd be great if you can also provide more details about STR.

I have been unable to get the failure to occur if I start http logging up front, but have had it reoccur when it is not started. Perhaps logging is changing timing, and/or causing serialization to occur which prevents the failure from starting?

I have disabled config security.tls.enable_0rtt_data as requested, and will see if the failure has been resolved.

I don't know what you want when you asked "can also provide more details about STR."

FYI, the problem has not reoccurred since I changed the setting of security.tls.enable_0rtt_data to disabled.

The severity field is not set for this bug.
:kershaw, could you have a look please?

For more information, please visit auto_nag documentation.

The severity field is not set for this bug.
:dragana, could you have a look please?

For more information, please visit auto_nag documentation.

gregdyck, are you using any firewall? For example, Sophos has a known issue with 0RTT.

Dennis, do you know of any change related to 0RTT in Fx 100? In bug 1770742 I have fixed a problem with our retry mechanism. n the log from this bug I do not see SSL_ERROR_BAD_MAC_ALERT error only NET_RESET.

There were no changes to 0RTT in NSS 3.77 which shipped with Fx 100.

I can confirm the problem is gone for me after disabling security.tls.enable_0rtt_data
Also, I have Sophos installed

Yes, Sophos was pre-installed on my system by corporate policy. It can not be removed.

This is the mitigation when a firewall disallows Firefox to use 0RTT. A new pref is added to control whether to always use 0RTT for HTTP/2.
When the pref is false, nsHttpTransaction::Do0RTT is called before trying 0RTT.

Lower the severity a bit, since it seems the failure of 0RTT is not caused by a firewall or a middle box.
We are also discussing a better retry algorithm to fix this kind of issues once for all.

Backed out for multiple failures
Push with failures: https://treeherder.mozilla.org/jobs?repo=autoland&group_state=expanded&selectedTaskRun=HA0TT3GURrqVcUVTx--OfQ.0&resultStatus=testfailed%2Cbusted%2Cexception%2Cretry%2Cusercancel&revision=d6caea480d4d15e816fa9f47f66a4d89c715f8c2
Failure log:

• mochitest failure: https://treeherder.mozilla.org/logviewer?job_id=390935573&repo=autoland&lineNumber=3064
• build bustage: https://treeherder.mozilla.org/logviewer?job_id=390940786&repo=autoland&lineNumber=28335

Backout: https://hg.mozilla.org/integration/autoland/rev/c9fdd7b94fa7c572422e6af2c234646011c3396f

https://hg.mozilla.org/mozilla-central/rev/48faf80010b4