So what is the site?

You can try to disable IPv6 (check for other possible causes as well).

• https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can

WestEnd: NO site will load in Firefox when connected to the Internet through my VPN service, but these same sites, such as apple.com, google.com, and even mozilla.org, DO load in other browsers (Safari, Opera) when connected through my VPN.

cor-el: I read the article you linked to but, since I was wary about disabling IPv6 and "voiding my warranty," I did not do that; however, your answer inspired me to google IPv6 and I found a web site that tests for IPv6 connectivity. The results of that test (see attached screen captures) indicate that my ISP is not IPv6 compliant. BUT, Firefox can load all these sites when I connect to the Internet through my ISP, but can't when connected through my VPN, yet the other browsers can do so when using either method of connection to the Internet, so I don't understand why Firefox (v.62.0.3) can't?

As you can see, I'm not familiar with much of this, so I appreciate your help and patience, and will be forced to use another browser if I wish to connect to the Internet using a VPN, even though my preference is to use Firefox.

try to disable tracking protection:

• https://support.mozilla.org/en-US/kb/tracking-protection

thanks for the suggestion, FFus3r. I tried disabling tracking protection as you suggested, but it did not solve the problem. I tried accessing apple.com first using my VPN, then using my normal ISP - using my normal ISP, the page loaded almost instantaneously; connecting through my VPN, the same page did not load at all in the minute or so that I waited. :(

Are there any error messages in the Browser Console about the VPN?

• "3-bar" menu button or Tools -> Web Developer
• https://developer.mozilla.org/en-US/Tools/Browser_Console

You can check the Network Monitor to see if content is blocked or otherwise fails to load.

• https://developer.mozilla.org/en/Tools/Network_Monitor

If necessary use "Ctrl+F5" or "Ctrl+Shift+R" (Mac: Command+Shift+R) to reload the page and bypass the cache to generate a fresh log.

There is a DNS lookup tool available on the about:networking page that you can try.

See also:

• https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can

Hi, cor-el,

thanks for the reply.

I tried loading apple.com, connecting through my VPN and am attaching the results I got when using the Browser Console and the Network Performance analyzer. The results are attached. The image for the Browser Console results is small due to size limitations in the forum, so I don't know if you'll be able to see the results, though there were a lot of "Unknown localization messages" shown in the results.

I have no idea what the results mean, or if they will help analyze the problem. Also, since the page failed to load (a "Server can't be found" error message appeared after the browser tried for over a minute to load the page), the performance analyzer window pane shows no results.

I guess I'll try the DNS lookup tool you also suggested and will post the results when I get them.

Thanks, again, for your help. And, I did read that forum post you referred to, and mentioned this in an earlier post in this thread.

Hi, again, cor-el,

Just adding this post to show you the results of the DNS lookup that you suggested I try.

Incidentally, I also tried the DNS option in the about:networking page and, I don't know if this is important, but all the "TRR" results showed "false" when I tried to access apple.com through my VPN. Like I said before, accessing apple.com through my normal ISP resulted in the page loading immediately, so there must be some conflict somewhere having to do with Firefox and my VPN.

Thanks, again.

You mention TRR.

Is TRR enabled or disabled if you check the related pref(s) on the about:config page?

• network.trr.mode = 0

I didn't open "about:config" due to the warning about "voiding warranty" but, when I opened the Browser Console, I got the messages shown in the attached screen shot. Hope that helps!

Btw, can you give any advice about proceeding past the warning in "about"config" that I get?

Thanks.

Is there a reason why you can't just go to the site without VPN? Could be my guess that with the VPN the site can't determine your originating location so it doesn't permit the site to be displayed.

teke978 said

Btw, can you give any advice about proceeding past the warning in "about"config" that I get?

The voiding warranty is just humour on being careful on the Preferences you modify. Some Preferences can indeed cause issues if you change from the default setting. Some Preferences can get modified as you change settings in Options/Preferences panel in Firefox. Just click on the blue accept risk button.

http://kb.mozillazine.org/about:config

cor-el said

Are there any error messages in the Browser Console about the VPN?

• "3-bar" menu button or Tools -> Web Developer
• https://developer.mozilla.org/en-US/Tools/Browser_Console

You can check the Network Monitor to see if content is blocked or otherwise fails to load.

• https://developer.mozilla.org/en/Tools/Network_Monitor

If necessary use "Ctrl+F5" or "Ctrl+Shift+R" (Mac: Command+Shift+R) to reload the page and bypass the cache to generate a fresh log. There is a DNS lookup tool available on the about:networking page that you can try. See also:

• https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can

Don't know if this will help, but I'm attaching screenshots about TRR, Network, and the Browser Console, to answer your previous questions, and those of others.

One thing that has me completely confused is why there aren't these problems with any browsers other than Firefox - I could use them, and do if I have to, but I'd prefer to use Firefox due to its reported security features, as well as the add-ons that are available.

Thanks for all your help! :)

WestEnd said

Is there a reason why you can't just go to the site without VPN? Could be my guess that with the VPN the site can't determine your originating location so it doesn't permit the site to be displayed.

I just prefer to use VPN to access some sites, and I can do that with all the other browsers I tried using, like Safari, Opera, and Chrome, just not Firefox, and I would prefer to use Firefox for its reported security features, as well as the add-ons that are available for it.

Looks like everyone is stumped :(

teke978 said

WestEnd said

Is there a reason why you can't just go to the site without VPN? Could be my guess that with the VPN the site can't determine your originating location so it doesn't permit the site to be displayed.

I just prefer to use VPN to access some sites, and I can do that with all the other browsers I tried using, like Safari, Opera, and Chrome, just not Firefox, and I would prefer to use Firefox for its reported security features, as well as the add-ons that are available for it.

Since no one knows what VPN your using no one is going to be able to help. So in reality no one is stump when there is lack of information that isn't provided.

WestEnd said

teke978 said

WestEnd said

Is there a reason why you can't just go to the site without VPN? Could be my guess that with the VPN the site can't determine your originating location so it doesn't permit the site to be displayed.

I just prefer to use VPN to access some sites, and I can do that with all the other browsers I tried using, like Safari, Opera, and Chrome, just not Firefox, and I would prefer to use Firefox for its reported security features, as well as the add-ons that are available for it.

Since no one knows what VPN your using no one is going to be able to help. So in reality no one is stump when there is lack of information that isn't provided.

No one asked which VPN I'm using, as far as I can see, and I answered everyone's questions as best I could so, if someone needs more info that I can give them, I will. Btw, I'm using PIA (Private Internet Access) VPN service.

Also, there was a recent update to Firefox and I installed it, but there was no change - Firefox still won't load web pages when connected to the Internet via VPN, though Opera, Chrome and Safari do so without problem, as did Firefox prior to macOS 10.14.