Why would I get server cannot be contacted after a few hours of browsing?
I've had this problem since for several years, probably going back to v15 or so. Firefox loads and works fine for a while. Then, suddenly, for reasons I do not understand, it refuses to load any more webpages. I get a "server cannot be found" error. It's like Firefox forgets how to do an IP lookup, or gets a bogus answer that redirects to an IP that is bogus. It doesn't wait or timeout either. Once I get it once I cannot browse to any website until I close Firefox and reopen the program. Even opening new browser tabs or windows doesn't help. I have to completely exist Firefox (all instances).
I would like to note that if it is "about to break", when I click a link, bookmark, or type in the web address, when I hit enter it fails within a second or two. It doesn't sit around and timeout after 30 seconds.
I don't feel like I'm doing anything that is out of the ordinary. I have a few plugins, but this happens on multiple computers, including some that have no plugins disabled.
Here's things that may be affecting this behavior for me:
1. I use a hosts file to block a lot of spammy websites. I use a program called hostsman to handle the hosts file. I have the DNS service disabled because it cannot handle the number of entries that are in the hosts file. (been using this for more than 10 years) 2. I have disabled disk caching (I use an SSD and I have found that disk caching creates more problems for browsing than its worth). I still do the in-RAM caching, and it's not uncommon for Firefox to be using 1GB of RAM or so. I don't think I've ever seen it use more than about 1.2GB of RAM. All of the systems have massive amounts of free RAM. My main desktop has 64GB of RAM, with 75-80% of it free typically.
I've also seen this at different physical locations (home, work, other side of the country at friend's house's, etc.). This problem only affects Firefox. I haven't seen it on Chrome or Internet explorer (albeit I don't use them for hours on end). I typically have this issue a few times a day. I do work from home, and most of my work is in the browser, so it can be a bit annoying.
Right now my hardware on this machine is:
Lenovo Y55 with 16GB of RAM, i7-4700HQ and 512GB SSD. Other systems are far more powerful than this one, so I tend to think that hardware is not the problem.
Thanks.
All Replies (4)
I don't have an answer for you, but we did receive some reports of this after the release of Firefox 36. One Firefox 36 user also believed that Firefox had stopped sending DNS requests, which is a prerequisite to being able to connect to the web server. Perhaps it became more frequent for you as well, since otherwise, you probably would have posted this a few years ago...
I don't recall that we identified the source of the problem, but in many cases, it was "something" in the settings folder.
Along those lines, could you conduct this test:
Create a new Firefox profile
This is in addition to and does not replace your existing settings.
A new profile will have your system-installed plugins (e.g., Flash) and extensions (e.g., security suite toolbars), but no themes, other extensions, or other customizations. It also should come with completely fresh settings databases and a fresh cache folder.
Exit Firefox and start up in the Profile Manager using Start > search box (or Run) -- type or paste the following and press Enter:
firefox.exe -P
Don't delete anything here.
Any time you want to switch profiles, exit Firefox and return to this dialog.
Click the Create Profile button, assign a name like April7, and ignore the option to change the folder location. Then start Firefox in the new profile you created.
It might take a while to determine whether the new profile is works better than your old one. If you want to import your bookmarks from your regular profile during that time, here's how:
You can use the Library dialog (Ctrl+Shift+b or "Show All Bookmarks") to access the Restore feature. The trick is knowing where to find your bookmark backups in your regular profile. After clicking Choose File... you can paste this into the file name space and press Enter to drill down to your profile folders:
%APPDATA%\Mozilla\Firefox\Profiles
The semi-randomly-named folder that has your last backup is usually the one ending with "default". Click into that one, then into the bookmarkbackups folder. Here you can pick the most recently updated file to restore.
Important: restoring a bookmark backup wipes any bookmarks currently in your active Firefox profile and replaces it with the contents of the backup file.
I think it's also reasonable to install AdBlock Plus, LastPass and SQLite Manager, as those, by themselves, are unlikely to be the source of this seemingly rare problem. But I wouldn't add all your extensions at once to the new profile.
I have the same problem but it does not happen in several hours but a couple, 1 or 2 hours at most. Browsing like normal, visiting websites, downloading images, videos and all of the sudden it stops working and "cannot find server" message appears on all tabs or windows.
Only solution is to close all FF windows and reopen a new one.
- Tests made:
Removed all plugins. Deleted all history and browsing data. Deleted all profiles. Clean reinstall of FF completely. (new profile/no-ext/no-plugins)
These tests were made one at a time but they all had the same result. This issue began around v36-37 for me as well. as of v40.0.3 issue still happens.
Last time it stopped working attempted the Firefox Health Report it did not load at first time, a 2nd time it worked but then it did not load a 3rd time with the same canot find server msg.
Hi LoneTiger, are you still running Windows 7?
When this problem occurs, does Firefox indicate that it is "offline"? That would be indicated either on:
- "3-bar" menu button > Developer
- (menu bar) File menu
I don't have any new information other than what was listed earlier in this thread.
@jscher2000
Yes running Windows 7 pro here.
No, when FF stopped working I checked and it showed as normal, not offline. Out of curiosity went offline mode and then back normal mode but no change, FF would still refuse to find server addresses.