How to Solve a 502 Bad Gateway Problem
If a "502 Bad Gateway" error occurs when you attempt to access the Internet, the Web server received an invalid response. The error may occur on a single computer or across the entire network. Depending on which issue is the cause, you have several options to resolve the problem.
Clear the system cache on the computer that is having the issue. Go to "Tools" in Internet Explorer to delete "Temporary Internet Files" and "Cookies." Be sure that the box for "Preserve Favorite Website Data" is not checked.
Select "Tools" and "Internet Options." Click the "Connections" tab and select "LAN Settings." The standard default is to select "Automatically Detect Settings" or to have all three of the boxes blank. Check with your network administrator if you see a different configuration.
Reboot the computer in Safe Mode and run a full virus scan. Some viruses block Internet connection and may produce error codes.
Check the server that is managing the Internet connection. Confirm that it is able to connect to the Internet. If so, check the connections and settings for the network.
Check the Internet connection coming in from the Internet Service Provider with direct connection to a computer. Determine if the error occurs on any computer. If not, check the server network connections.
Contact your Internet service provider to see if there is a network outage. Your ISP can run tests to determine where the issue is occurring between the system and your network.