Does it make any difference if you experiment with the DNS over HTTPS setting? See: Firefox DNS-over-HTTPS

Does it make any difference if you switch Firefox to working offline for 60 seconds, then turn it back to normal? To do that, call up the File menu (Alt+F) and then click Work Offline.

Unfortunately no, it doesn't make any difference in either case.

However trying to refresh the page, while network in dev tools is open , I can see that a request is being aborted by NS_BINDING_FAILED message.

The only way to make it work is closing Firefox (making sure it is terminated in task manager) and open again.

Also this issue only happens with HTTPS which I guess need to verify the certificate before trying to make connection

Using the SWAG method, Would you be willing to try the Addon - HTTPS Everywhere -- ? FF's Setting was too problematic and I returned to this Addon. See - Install in FF - Link .....

https://addons.mozilla.org/firefox/addon/https-everywhere/

Firefox can generate quite verbose logs of connection attempts, but I'm not sure how to interpret them:

https://firefox-source-docs.mozilla.org/networking/http/logging.html

The fact that takes some time to develop is the most peculiar aspect of the problem. Does it mean that other open connections are saturating Firefox's ability to make connections? Or is some other process on the system taking time to detect that Firefox is running? Or is Firefox making an automatic connection that triggers some kind of gating mechanism? (How to stop Firefox from making automatic connections) Or something else?

Have you already tried:

New Profile Test

This takes about 3 minutes, plus the time to test your problem site(s).

Inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it.

Take a quick glance at the page and make a mental note of which Profile has this notation: This is the profile in use and it cannot be deleted. That is your current default profile.

Click the "Create a New Profile" button, then click Next. Assign a name like Feb2022, ignore the option to relocate the profile folder, and click the Finish button.

Firefox will switch your default profile to the new one, so click the Set as Default Profile button for your regular one to avoid an unwanted surprise at your next startup.

Scroll down to Feb2022 and click its Launch profile in new browser button.

Firefox should open a new window that looks like a brand new, uncustomized installation. (Your existing Firefox window(s) should not be affected.) Please ignore any tabs enticing you to connect to a Sync account or to activate extensions found on your system to get a clean test.

Is the pattern any different in the clean profile?

When you are done with the experiment, you can close the extra window without affecting your regular Firefox profile. (Feb2022 will remain available for future testing.)

Using the SWAG method, Would you be willing to try the Addon - HTTPS Everywhere -- ? FF's Setting was too problematic and I returned to this Addon. See - Install in FF - Link ..... https://addons.mozilla.org/firefox/addon/https-everywhere/

I did mention that issue happens with HTTPS access, so I'm not sure how using an extension that just changes the HTTP to HTTPS would make any difference.

Firefox can generate quite verbose logs of connection attempts, but I'm not sure how to interpret them: https://firefox-source-docs.mozilla.org/networking/http/logging.html The fact that takes some time to develop is the most peculiar aspect of the problem. Does it mean that other open connections are saturating Firefox's ability to make connections? Or is some other process on the system taking time to detect that Firefox is running? Or is Firefox making an automatic connection that triggers some kind of gating mechanism? (How to stop Firefox from making automatic connections) Or something else? Have you already tried: New Profile Test This takes about 3 minutes, plus the time to test your problem site(s). Inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it. Take a quick glance at the page and make a mental note of which Profile has this notation: This is the profile in use and it cannot be deleted. That is your current default profile. Click the "Create a New Profile" button, then click Next. Assign a name like Feb2022, ignore the option to relocate the profile folder, and click the Finish button. Firefox will switch your default profile to the new one, so click the Set as Default Profile button for your regular one to avoid an unwanted surprise at your next startup. Scroll down to Feb2022 and click its Launch profile in new browser button. Firefox should open a new window that looks like a brand new, uncustomized installation. (Your existing Firefox window(s) should not be affected.) Please ignore any tabs enticing you to connect to a Sync account or to activate extensions found on your system to get a clean test. Is the pattern any different in the clean profile? When you are done with the experiment, you can close the extra window without affecting your regular Firefox profile. (Feb2022 will remain available for future testing.)

Thank you for trying to help, I also mentioned, Installed every Firefox from 90 and above, which means they are all new. The only changes that I always make are:

• Disable Firefox calling home (Firefox Data Collection section only and I know that is not only place it calls home)
• Disable Firefox from calling google too (Deceptive Content and Dangerous Software Protection) and (Query OCSP responder)
• Disable Enhance Tracking Protection (causes connection to half of AWS services to fail)
• Obviously dumb auto update system that doesn't even ask me if I want to update, to avoid just having latest version in all folders.

Thank you for trying to help, I also mentioned, Installed every Firefox from 90 and above, which means they are all new. The only changes that I always make are:

• Disable Firefox calling home (Firefox Data Collection section only and I know that is not only place it calls home)
• Disable Firefox from calling google too (Deceptive Content and Dangerous Software Protection) and (Query OCSP responder)
• Disable Enhance Tracking Protection (causes connection to half of AWS services to fail)
• Obviously dumb auto update system that doesn't even ask me if I want to update, to avoid just having latest version in all folders.

And if you run an uncustomized standard release (Firefox 96.0.3) profile, as proposed in my previous reply, how long before the problem manifests itself? (Firefox should still observe the auto-update setting set in the earlier standard release profile because that is stored in the C:\ProgramData\Mozilla\updates folder and not an individual profile.)

I installed version 97.0 (all EMEfree) and still the same issue happens, but this time resolution is faster, I get following error in less than 5 seconds.

Error code: SSL_ERROR_HANDSHAKE_UNEXPECTED_ALERT

When I refresh the page, resources are randomly retrieved from website, but most of them fails. After few minutes of browsing, even refresh completely fails and I have to restart firefox and it immediately re-connects.

Again, I need to emphasis whatever the changes were, happened after firefox 90 all other firefox versions before 90 (currently 87, 88,89) have no issues, and I have installation of 80 too and that one has no issue either.