Diễn đàn hỗ trợ Firefox

For over a year, my browser occasionally loses connectivity. It may work for 3 hours or 3 days, but inevitably new tabs will stop working and then slowly the others will stop as well. When this happens, none of my other browsers are impacted. They work fine. It is only Firefox. The only solution is to close everything and lose all my work.

Once I do that and restart Firefox, I receive an error message telling me I am using an older version of Firefox that is not compatible with my profile. The only solution that brings me back to the best starting place is to re-install Firefox.

My company IT spent 3 days trying to find the problem and couldn't. I have uninstalled and reinstalled so many times. All extensions are turned off, as are the two add-ons. I have been using Firefox for over a decade and prefer it to all other browsers, but I need to find a solution or I am going to have to move on. Help!!!

NOTE: I have marked this as "Solved" because I figured out the problem described below, and I fixed it. See my following message here for a description of my solution.

Original message starts here ...

I'm using Firefox 144.0 under Debian Linux. I've used Firefox on this machine for years with no problem. Firefox can easily connect to literally thousands of web servers on the internet, both via HTTP and HTTPS.

But now, I'm having an issue:

I started running a web server on the same machine that Firefox is running on. This server only listens for non-HTTPS connections on port 80. I am not using any proxy server with Firefox.

I can easily and directly connect to my local web server's pages from my local machine from Chrome, w3m, curl, and direct telnet connections to port 80 ... all of which are addressing the publicly accessible domain name for my local web server. However, However, Firefox refuses to connect to any URL's on my local machine, and it gives me the following explanation:

Unable to connect

Firefox can’t establish a connection to the server at [ my server's domain name ].

   The site could be temporarily unavailable or too busy. Try again in a few moments.
   If you are unable to load any pages, check your computer’s network connection.
   If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the web.

In Firefox, I have all auto-forcing of HTTPS disabled by means of Don’t enable HTTPS-Only Mode turned on.

I get the same error in Firefox whether I connect via a URL like "http://MYFULLDOMAINNAME" or a URL like "http://AAA.BBB.CCC.DDD", where "AAA.BBB.CCC.DDD" is my machine's publicly accessible static IP address and "MYFULLDOMAINNAME" is the long-standing, publicly accessible domain name for my machine ... both with and without a suffix of ":80" on the supplied URL.

And again, all other browsers on my machine have no problem whatsoever connecting to my own local web server on this same local machine of mine using those same URL's.

And all browsers (Firefox and otherwise) that are running on other machines all over the internet have no problem connecting to that same web server via the same URL's that I described above

Also, I have no firewall rules on my machine which would block access to my own machine's port 80.

What could be causing this error in Firefox, and what might I be able to do to fix it?

Thank you very much in advance.

UPDATE: Just a bit more information. Looking at the web logs, I see that Firefox's request never even reaches my local web server. In other words, Firefox itself is not even trying to make a TCPIP port 80 connection to my local web server in the first place

I need help with a problem that has tortured me for weeks. I use debian 13 with plasmakde. I don't know why, but when I connect to a wifi after some time it doesn't work anymore ONLY with Firefox. I can perfectly use any other app which requires internet but firefox. Sometimes it gives me the error "The connection has timed out", sometimes the error "Unable to find the proxy server" (even if I selected no proxy in the network settings). I searched online but I couldn't find anything helpful, so I can only hope to find a solution in here. Thank you very much in advance!

bold text When I try to go to my "FIREFOX" it answers me in French of course but here you don't accept to write me in French and so it's very difficult for me ... (could you help me for this of course ???) : "hmm this adress doesn' seem to be valid." Hum, cette adresse ne semble pas valide.

What must I do please ??? [edited from public] @orange.fr

Hmm. We’re having trouble finding that site.

We can’t connect to the server at healthy.kaiserpermanente.orghttps.

If you entered the right address, you can:

   Try again later
   Check your network connection
   Check that Firefox has permission to access the web (you might be connected but behind a firewall)

What does this mean and how do we fix it?

i want to access www.fintreeindia.com i pursue professional courses that's my class website and also i could not access youtube also my exam are nearly

Hi; I've signed up for the vpn, several times, but nothing appears. I don't see any box on the top right of any bar. I don't even know the symbol, but have checked all that are there. How do I turn it on? I found something about "privacy windows" but that just leads back to the signup page. I know it'll be simple, but I'm missing it totally.

I had a proxy set manually before and it was working just well, after I updated firefox it stopped asking for username password for my proxy and I keep getting no network error on every website I check. I also reentered the proxy data again and checked somethings in the about:config page to be true but still doesn't work.