Make sure you are not blocking content.

Start Firefox in Safe Mode {web link}

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

One issue that seems more common lately is Firefox's Tracking Protection feature. When it is blocking content in a page, a shield icon will appear at the left end of the address bar next to the padlock icon. This article has more info on managing this feature: Tracking Protection {web link}

Ok, so I tried running Firefox in safe mode and the problem still occurs.

Question, wouldn't have completely resetting Firefox eliminated the need to try safe mode? How is running safe mode any different?

Also, when resetting Firefox any settings, including content blocking, would have been reset to their default settings. Which specifically for content blocking would be not blocking anything except when in private windows (which I am not using). How could this be having an effect on the current problem?

Were you unable to replicate the problem?

So I have done some additional testing and have found out that resetting Firefox actually caused the problem to occur on 4channel.org as well.

I also tried on the Android app, version 64.0.1, and the problem is occurring there as well for both 4chan.org and 4channel.org.

Hello graphicjazz,

What you should do is use these links instead of the ones you mentioned :

http://www.4chan.org/

and :

https://www.4channel.org/

And the images load just fine .....

Okay, I just tried that and using those URLs work, but in Chrome I don't have to add the www however I did notice that it puts it there automatically.

So is it a bug in Firefox that it isn't automatically adding the www like Chrome?

graphicjazz said

Okay, I just tried that and using those URLs work, but in Chrome I don't have to add the www however I did notice that it puts it there automatically. So is it a bug in Firefox that it isn't automatically adding the www like Chrome?

I tried it in Edge : same thing there - apparantly Chrome doesn't care about using proper URLs ......

May I suggest that you only use this URL :

https://www.4channel.org/

And maybe bookmark it  ?

Thanks for the suggestion. I did try several other websites in Firefox without putting the www in the URL and all of them added it automatically. So I guess there is something different about 4chan and 4channel that is not compatible with Firefox. I wouldn't be surprised if there are other websites out there with the same problem.

I'll just try to remember to put www at the beginning of the URL if I try websites in the future and they are not working properly.

This will have to suffice as a workaround until this can get corrected.

The CDN server uses hotlink protection and is checking the referrer.

• http://i.4cdn.org/co/1545697573377s.jpg

If the referrer is omitted (blank) then it works all the time. The http://4chan.org referrer is blocked, but the http://wwww.4chan.org referrer is accepted.

Okay, that makes sense as to why not having the www in the URL doesn't allow the images to load.

Hopefully Firefox will get fixed so that it will automatically add the www to the URL when needed like Chrome does.

Until then the workaround for manually adding www for sites that Firefox doesn't automatically add it to will have to suffice for now.

Firefox will only add the www. prefix with an open HTTP connection when the DNS lookup of the domain without this prefix isn't working. With a secure connection there is never a fixup tried and you need to type the full host path.

In this case both 4chan.org and www.4chan.org work as you can test via the DNS Lookup tool on the about:networking page via the location/address bar.

Do you mean a secure connection as in using HTTPS vs HTTP?

I am not using HTTPS with 4chan if so.

I do see what you mean about both 4chan.org and www.4chan.org resolving in the DNS Lookup tool.

I tried a few sites that I tried earlier where Firefox automatically added the www and found that they also have URLs that resolve both with and without the www prefix.

bbc.com sciencemag.org ucla.edu worldbank.org un.org ox.ac.uk wikia.com

All of these sites default to HTTP not HTTPS, automatically add the www prefix in Firefox, and resolve to IP addresses using the DNS Lookup tool with and without the www prefix.

So there is something that 4chan and 4channel has that is breaking Firefox.

I would think it highly probable that there are more sites out there that exhibit the same behavior.

Some web servers like bbc.com send a status code 301 Moved Permanently and redirect via the location header (Location: http://www.bbc.com/), so in these cases you always end up with the www. prefixed version.

You can check this in the Network Monitor.

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

So I've been going through some testing and I found that apparently Chrome doesn't natively redirect 4chan.org or 4channel.org to have the www prefix.

Apparently it was using my history to add the www prefix because when I cleared my browsing history in Chrome it does not redirect anymore.

This issue can now be considered solved on account of user error.

I don't consider this a user error. The server should redirect to the www. prefixed website if only this domain is working properly like BBC does, so maybe contact the website to look into this.