You could try creating a new profile: [Manager - Create, remove, or switch Firefox profiles]

Some problems occur when your Internet security program was set to trust the previous version of Firefox, but no longer recognizes your updated version as trusted. Now how to fix the problem: To allow Firefox to connect to the Internet again;

• Make sure your Internet security software is up-to-date (i.e. you are running the latest version).
• Remove Firefox from your program's list of trusted or recognized programs. For detailed instructions, see

Configure firewalls so that Firefox can access the Internet. {web link}

Hello,

Purging Firefox out of Ubuntu didn't help, issue still persists:

sudo apt remove firefox sudo apt purge firefox sudo apt autoremove sudo rm -fr /opt/firefox sudo rm -Rf /etc/firefox/ sudo rm -Rf /usr/lib/firefox*

and of course, deleting the hidden .mozilla folder at /home/user.mozilla/

Firewall instructions that are linked, they are relevant to Windows OS, not Unix systems. Nothing within the Firewall suggests that Firefox is blocked.

Tor Browser is behaving the same way.

Any logs I can find, to tell me what is causing this issue?

Thanx

When I do run or start Firefox from the terminal: $firefox I do get these lines, and I am not sure if it is related to the issue beforehand.

[Parent 38706, IPC I/O Parent] WARNING: FileDescriptorSet destroyed with unconsumed descriptors: file /build/firefox-iQ8SFg/firefox-85.0.1+build1/ipc/chromium/src/chrome/common/file_descriptor_set_posix.cc:19 [Parent 38706, IPC I/O Parent] WARNING: FileDescriptorSet destroyed with unconsumed descriptors: file /build/firefox-iQ8SFg/firefox-85.0.1+build1/ipc/chromium/src/chrome/common/file_descriptor_set_posix.cc:19 [Parent 38706, IPC I/O Parent] WARNING: FileDescriptorSet destroyed with unconsumed descriptors: file /build/firefox-iQ8SFg/firefox-85.0.1+build1/ipc/chromium/src/chrome/common/file_descriptor_set_posix.cc:19 [Parent 38706, IPC I/O Parent] WARNING: FileDescriptorSet destroyed with unconsumed descriptors: file /build/firefox-iQ8SFg/firefox-85.0.1+build1/ipc/chromium/src/chrome/common/file_descriptor_set_posix.cc:19 [Parent 38706, IPC I/O Parent] WARNING: FileDescriptorSet destroyed with unconsumed descriptors: file /build/firefox-iQ8SFg/firefox-85.0.1+build1/ipc/chromium/src/chrome/common/file_descriptor_set_posix.cc:19 [Parent 38706, IPC I/O Parent] WARNING: FileDescriptorSet destroyed with unconsumed descriptors: file /build/firefox-iQ8SFg/firefox-85.0.1+build1/ipc/chromium/src/chrome/common/file_descriptor_set_posix.cc:19 [Parent 38706, IPC I/O Parent] WARNING: FileDescriptorSet destroyed with unconsumed descriptors: file /build/firefox-iQ8SFg/firefox-85.0.1+build1/ipc/chromium/src/chrome/common/file_descriptor_set_posix.cc:19 [Parent 38706, IPC I/O Parent] WARNING: FileDescriptorSet destroyed with unconsumed descriptors: file /build/firefox-iQ8SFg/firefox-85.0.1+build1/ipc/chromium/src/chrome/common/file_descriptor_set_posix.cc:19 [Parent 38706, IPC I/O Parent] WARNING: FileDescriptorSet destroyed with unconsumed descriptors: file /build/firefox-iQ8SFg/firefox-85.0.1+build1/ipc/chromium/src/chrome/common/file_descriptor_set_posix.cc:19 [Parent 38706, IPC I/O Parent] WARNING: FileDescriptorSet destroyed with unconsumed descriptors: file /build/firefox-iQ8SFg/firefox-85.0.1+build1/ipc/chromium/src/chrome/common/file_descriptor_set_posix.cc:19 [Parent 38706, IPC I/O Parent] WARNING: FileDescriptorSet destroyed with unconsumed descriptors: file /build/firefox-iQ8SFg/firefox-85.0.1+build1/ipc/chromium/src/chrome/common/file_descriptor_set_posix.cc:19 [Parent 38706, IPC I/O Parent] WARNING: FileDescriptorSet destroyed with unconsumed descriptors: file /build/firefox-iQ8SFg/firefox-85.0.1+build1/ipc/chromium/src/chrome/common/file_descriptor_set_posix.cc:19

... etc until Firefox is shut down (or 'kill' terminal)

Thanx

An update:

I did install Firefox from Snap (as a source and through Snap). And Snap Firefox is loading without a problem.

I did not install Firefox from repository: ubuntu-focal-security-main (Ubuntu 20.04.2 LTS);

I did not install Firefox from Firefox repository: $ wget -O ~/FirefoxSetup.tar.bz2 "https://download.mozilla.org/?product=firefox-latest&os=linux64"

That is because both sources above, Ubuntu's and Firefox's, the Firefox from both sources will not 'work' properly.

Thanx

Can you open internal pages like about pages listed on about:about ?

Hello,

"Can you open internal pages like about pages listed on about:about ?"

about:config within the URL bar, would yield to the same thing, nothing is moving or showing; same issue.

It is something within Firefox and Ubuntu, rather than the firewall or Firefox profiles/settings.

Thanx

You can try to start Firefox via a terminal window to see if you get errors reported.

You can try to start Firefox via a terminal window to see if you get errors reported.

Hello cor-el,

If I do run $firefox via the terminal this what I do get:

[Parent 38706, IPC I/O Parent] WARNING: FileDescriptorSet destroyed with unconsumed descriptors: file /build/firefox-iQ8SFg/firefox-85.0.1+build1/ipc/chromium/src/chrome/common/file_descriptor_set_posix.cc:19 [Parent 38706, IPC I/O Parent] WARNING: FileDescriptorSet destroyed with unconsumed descriptors: file /build/firefox-iQ8SFg/firefox-85.0.1+build1/ipc/chromium/src/chrome/common/file_descriptor_set_posix.cc:19 [Parent 38706, IPC I/O Parent] WARNING: FileDescriptorSet destroyed with unconsumed descriptors: file /build/firefox-iQ8SFg/firefox-

Thanx

Hello,

Issue also being experienced when I do install and fire up Tor Browser.

Thanx