Hello together. I'm experiencing the same problem as discussed in this cases that is not solved yet: https://support.mozilla.org/en-US/questions/1312836 https://support.m… (read more)
I'm experiencing the same problem as discussed in this cases that is not solved yet: https://support.mozilla.org/en-US/questions/1312836 https://support.mozilla.org/en-US/questions/1333547 https://support.mozilla.org/en-US/questions/1321038
Symptoms: After FF starting it loads pages fast enough. After several minutes of using pages start be loading very slow. Loading slowness increases until it becomes blocked continuously. Reload button has no effect. I tried everything from here: https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can - No effect.
Work around done: When windows is loading in Safe Mode the problem disappeared. If I disable Windows Defender Firewall the the problem disappear and appear after firewall enabling again in several minutes (same as after FF restarting) When I go to <current network settings> and switch Network Profile from Public to Private or from Private to Public the problem disappear but goes back just in several minutes (same as after FF restarting). Windows 10 Restorehealth has no effect, and reports that everything is OK with system files (DISM.exe /Online /Cleanup-image /Restorehealth ) The most strange thing Windows 10 In-place Upgrade has no effect.
I found out the core of problem is that Windows Firewall is blocking FF internal interprocess communication on local TCP ports. Yes, you would say it is not possible and firewall doesn't affect local port communication but in my case it is a fact. I used the ProcessMonitor from Windows Sysinternals, and Windows Defender Firewall with Advanced Security log. Screenshots shows this fact. On first two lines from Firewall log you see a Local Port Communication blocking, on ports 1401 and 1400. Next Screenshot from ProcessMonitor shows (see blue colored lines) that it was exactly FF communication, where I was trying to reload a page several times.
Any ideas what to do with it? It seems like Microsoft’s way fighting a concurrent web browsers, but I hope it isn’t.
Now I use FF version 94 but the problem starts from 88. I was trying FF downgrading to version 75 with no effect.