Error loading websites

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This article offers solutions to errors you may receive in Firefox or Mozilla Suite when attempting to connect to some or all websites. Error messages may include "The document contains no data" and "The connection was refused when attempting to contact..." or an error page may tell you that the server could not be found or that the connection has timed out.

If you can't get any website to load immediately after updating your browser, it is almost certainly your firewall blocking the connection.

Error loading any website

If Firefox/Mozilla Suite will not connect to any website:

  • As with anything else, the problem may go away once you reboot your system.
  • Make sure you are connected to the Internet. To make Firefox/Mozilla Suite autoconnect when it starts, see this article.
  • Make sure that File -> Work Offline is not checked.

Only Mozilla applications are having problems

If Firefox/Mozilla Suite/Thunderbird can't connect and other programs such as Internet Explorer can...

Connection settings

Make sure your connection settings are correct. If you have Internet Explorer and it works, compare Internet Explorer's connection settings (e.g., Control Panel -> Internet Options -> Connections: LAN) to those of Firefox (Tools -> Options -> General -> Connection Settings) or Mozilla Suite (Edit -> Preferences -> General -> Connection Settings).

If your Firefox or Mozilla Suite connection settings are not correct but any changes you try to make are not saved after restarting the application, make sure you don't have a utility program such as "Hide IP Platinum" that modifies your connection settings. Even if the utility is no longer installed, the user.js file may still contain the modified settings [1]. To resolve this problem, open the profile folder and look for a user.js file. If found, either remove the user.js file or edit it to remove any "proxy" settings it may contain as outlined here, then reset the connection settings.

Cookies

Make sure to (at least temporarily) accept cookies from the website you are trying to connect to.

Firewalls

Make sure that your firewall program is configured to allow internet access to Firefox/Mozilla Suite. Most firewalls will ask you whether to allow a new program to connect to the internet, so it is important to always allow access for new or updated Mozilla applications. Even if you see permission in the firewall list of permitted programs, it could be for the previous program version, as firewalls require permission to allow an updated program to access the internet [2].

Some firewalls can be rather tricky to configure, or even to disable or uninstall. The "EnumProcess" tool for Windows, available here, enumerates all running processes and tries to find out if one or more of them are firewall processes. For more information on specific firewalls, including the Windows Firewall, Norton Internet Security, ZoneAlarm, McAfee, and others, see this article.

Panda Anti-Virus

Older versions of Panda Anti-virus can cause connection problems. (Information on this is no longer available on the Pandasoft Web site.)

IPv6

The problem may be with IPv6 ("Internet Protocol version 6"). To disable IPv6, change the preference network.dns.disableIPv6 from "false" to "true" . Here are the steps:

  1. Type about:config in the address bar, press Enter.
  2. Find network.dns.disableIPv6 in the list.
  3. Right-click -> Toggle.
  4. Restart Firefox/Mozilla Suite and try again.

If this doesn't work, re-enable IPv6 by resetting the preference to "false".

All programs are having problems

Router

A recently installed router can cause problems. Contact your system administrator or refer to your router's documentation. If possible, see if you can connect without hooking up to the router.

Viewing system logs

System event logs may contain information on important events such as service failures, and application updates and failures. For an example of an Internet service interruption, read this. To view the Windows Event Viewer, Start > Run > eventvwr.

DNS

If your domain name system server (DNS server) becomes overloaded, you may be unable to view some or all websites. Your DNS server translates web addresses (URLs) that you enter in your browser, into IP addresses that are used on the Internet. If you can open a website by entering the IP address into the Location Bar but not the URL (for example, if http://64.233.167.147 works but http://www.google.com doesn't) you may have a DNS problem.

You can check the speed of your DNS server by downloading the "wdnslookup" utility for Windows, available here. OS-X, Linux, and UNIX users can use program "nslookup", which is part of the operating system. Remember that both local DNS servers and your own computer cache the results, so a lookup may be much slower on the first attempt. For accurate results you should use the "Clear Cache" button in the wdnslookup utility before resolving the host name you enter. This will clear the DNS cache in your computer, but not the server cache. See this forum post for additional information.

The DNS server is usually provided by your Internet service provider so you should contact your ISP as a first step toward fixing the problem. One user had severe problems with multiple ISDN providers, but solved the problem [3] by finding a reliable DNS server. This explains how to find a more reliable DNS server and also discusses an alternative service called TreeWalk. This article tells how to increase the DNS query timeout period for Windows 2000.

A related DNS server issue that can result in failure of repeated attempts to open certain websites is that Windows 2000 and XP cache unsuccessful DNS lookup attempts. This means that you may not be able to view a particular website until the cached result expires. By default, the expiration time is 5 minutes. As a workaround, you can flush the DNS cache (For Windows XP, "Start -> Run -> ipconfig /flushdns") then try loading the site again. If you want, you can permanently disable negative caching by editing the registry, as shown here. The registry entry is officially documented here (Windows 2000) and here (Windows XP).

ISP

If programs other than Firefox/Mozilla Suite are also having problems connecting, the problem may be with your Internet Service Provider. Contact them.

Norton Internet Security

The popup blocker in the Addon Pack for Norton Internet Security can cause an interruption in the Symantec Network Proxy service, thereby interrupting your Internet connection.[4]

Trend Micro Anti-Virus

If you haven't updated your pattern file since April 2005 and suffer from 100% CPU utilization, read this.

Spyware and other malware

It is possible that Spyware or other malicious software or "malware" is causing connection problems. Use programs such as Ad-Aware or Spybot-S&D to scan your computer for malware.

Error loading some websites

If Firefox/Mozilla Suite can connect to some websites, but not others:

  • Try loading the same site from another computer or another browser. If you are still unable to load a specific site , the problem is likely with the website.
  • If you receive an error message from a website, the error message may be cached. Attempts to reload the site may yield only the cached error message. To force it to reload from the Web, hold down the <Shift> key and press the Reload button. See this discussion.
  • Clear the Cache. In Firefox 2: "Tools -> Options -> Advanced -> Network / Cache -> Clear Now". In Firefox 1.5 and earlier: "Tools -> Options -> Privacy -> Cache -> Clear Cache Now". In Mozilla Suite: "Edit -> Preferences -> Advanced -> Cache -> Clear Cache"
  • If the website is a secure site such as a bank, Paypal, eBay, or any site that begins with "https:", read the article, SSL is disabled.
  • The Outpost Pro Firewall can sometimes interfere with loading certain Websites.[5],[6]
  • Ad blocking can cause Web sites not to be displayed. This may be due either to an ad-blocking extension or to an external Internet security suite. An error message, "The connection to the server was reset while the page was loading," may be displayed. You may be able to determine that part of the site has been loaded by selecting "View > Page Source" from the menu.[7]
  • The website may have blocked your IP address.
  • If you enabled network.http.pipelining (a "tweak" designed to improve page loading time), disable it in about:config by typing "pipelining" in the filter and right-clicking all entries and choosing Reset. (If you set this preference by editing the user.js file, also remove this edit.)
  • A hosts file has the ability to redirect Internet requests. Review your hosts file to see if it contains any entries other than 127.0.0.1 localhost .
  • If repeated attempts fail to open a website, Windows may have cached an unsuccessful DNS lookup attempt. This means that you may not be able to view a particular website until the cached result expires. As a workaround, you can flush the DNS cache (For Windows XP, "Start -> Run -> ipconfig /flushdns") then try loading the site again. See this discussion and this example.
  • If you received the message, "This object has been blocked", see this article.
  • The website may only allow Internet Explorer users. You can work around this problem by installing a user agent spoofer, such as the User Agent Switcher extension, to make the website think you are using a different browser.
  • Make sure you type the address correctly.

Websites randomly don't load

If Firefox/Mozilla Suite randomly cannot connect to websites:

  • The site may be down or experiencing difficulties. Try loading the site from another computer or browser to see if this is the case.
  • If you enabled network.http.pipelining (a "tweak" designed to improve page loading time), disable it in about:config by typing "pipelining" in the filter and right-clicking all entries and choosing Reset. (If you set this preference by editing the "user.js" file, remove this edit.)
  • You may have problems with your domain name service (DNS).
  • Sometimes when you first try to use the Internet, your computer may take some time, perhaps up to a minute, to establish a connection. In this case, whichever application is first to use the Internet may experience temporary difficulty, but once a connection is established, all programs should work correctly.
  • Try disabling IPv6.
  • To determine if an extension is the cause of your problems try Safe_Mode. If that doesn't help, perform the full Standard_diagnostic.

See also

External links