Cannot Complete Request

Address Not Found

File Not Found

Invalid Address

Unknown Protocol

Failed to Connect

Network Timeout

Redirect Loop

Incorrect Response

Connection Interrupted

Document Expired

Offline Mode

Data Transfer Interrupted

Port Restricted for Security Reasons

Proxy Server Not Found

Proxy Server Refused Connection

Content Encoding Error

Unsafe File Type

Secure Connection Failed

Secure Connection Failed

Suspected Attack Site!

Blocked by Content Security Policy

Remote XUL

Corrupted Content Error

Additional information about this problem or error is currently unavailable.

The browser could not find the host server for the provided address.

  • Did you make a mistake when typing the domain? (e.g. ww.mozilla.org instead of www.mozilla.org)
  • Are you certain this domain address exists? Its registration may have expired.
  • Are you unable to browse other sites? Check your network connection and DNS server settings.
  • Is your computer or network protected by a firewall or proxy? Incorrect settings can interfere with Web browsing.
  • Could the item have been renamed, removed, or relocated?
  • Is there a spelling, capitalization, or other typographical error in the address?
  • Do you have sufficient access permissions to the requested item?

The provided address is not in a recognized format. Please check the location bar for mistakes and try again.

The address specifies a protocol (e.g. wxyz://) the browser does not recognize, so the browser cannot properly connect to the site.

  • Are you trying to access multimedia or other non-text services? Check the site for extra requirements.
  • Some protocols may require third-party software or plugins before the browser can recognize them.

Though the site seems valid, the browser was unable to establish a connection.

  • Could the site be temporarily unavailable? Try again later.
  • Are you unable to browse other sites? Check the computer's network connection.
  • Is your computer or network protected by a firewall or proxy? Incorrect settings can interfere with Web browsing.

The requested site did not respond to a connection request and the browser has stopped waiting for a reply.

  • Could the server be experiencing high demand or a temporary outage? Try again later.
  • Are you unable to browse other sites? Check the computer's network connection.
  • Is your computer or network protected by a firewall or proxy? Incorrect settings can interfere with Web browsing.
  • Still having trouble? Consult your network administrator or Internet provider for assistance.

The browser has stopped trying to retrieve the requested item. The site is redirecting the request in a way that will never complete.

  • Have you disabled or blocked cookies required by this site?
  • NOTE: If accepting the site's cookies does not resolve the problem, it is likely a server configuration issue and not your computer.

The site responded to the network request in an unexpected way and the browser cannot continue.

The network link was interrupted while negotiating a connection. Please try again.

The requested document is not available in the browser's cache.

  • As a security precaution, the browser does not automatically re-request sensitive documents.
  • Click Try Again to re-request the document from the website.

The browser is operating in its offline mode and cannot connect to the requested item.

  • Is the computer connected to an active network?
  • Press "Try Again" to switch to online mode and reload the page.

The browser connected successfully, but the connection was interrupted while transferring information. Please try again.

  • Are you unable to browse other sites? Check the computer's network connection.
  • Still having trouble? Consult your network administrator or Internet provider for assistance.

The requested address specified a port (e.g. mozilla.org:80 for port 80 on mozilla.org) normally used for purposes other than Web browsing. The browser has canceled the request for your protection and security.

The browser is configured to use a proxy server, but the proxy could not be found.

  • Is the browser's proxy configuration correct? Check the settings and try again.
  • Is the computer connected to an active network?
  • Still having trouble? Consult your network administrator or Internet provider for assistance.

The browser is configured to use a proxy server, but the proxy refused a connection.

  • Is the browser's proxy configuration correct? Check the settings and try again.
  • Does the proxy service allow connections from this network?
  • Still having trouble? Consult your network administrator or Internet provider for assistance.

The page you are trying to view cannot be shown because it uses an invalid or unsupported form of compression.

  • Please contact the website owners to inform them of this problem.
  • Please contact the website owners to inform them of this problem.

The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.

  • Please contact the website owners to inform them of this problem.
  • This could be a problem with the server's configuration, or it could be someone trying to impersonate the server.
  • If you have connected to this server successfully in the past, the error may be temporary, and you can try again later.

Attack sites try to install programs that steal private information, use your computer to attack others, or damage your system.

Website owners who believe their site has been reported as an attack site in error may request a review.

The browser prevented this page from loading in this way because the page has a content security policy that disallows it.

  • Please contact the website owners to inform them of this problem.

The page you are trying to view cannot be shown because an error in the data transmission was detected.

  • Please contact the website owners to inform them of this problem.

Or you can add an exception…