Difficulty: Moderately Easy
Step1
Error message 401, 403 or "Connection Refused by Host" means you are not authorized for this site. Try to enter the address again but if you continue to get this error message then you do not have authorization to access the webpage.
Step2
If you see error message 404 or "File Contains no Data," it means the web page does not exist. Just as with Step 1, check and enter the address again. If you receive the error message again then the website you are looking for is not there to view anymore.
Step3
Error message 400, "Failed DNS Lookup," or "Unable to Locate Server" means you may have entered the address incorrectly. Just as in the previous steps, check the address and try it again. If you receive the error message again then either the website no longer exists or you have the address wrong.
Step4
If you see error message 503 or "Unable to Locate Host," it means the web server or your ISP is down. First check your modem, router, and connection. If your equipment is functioning properly then the problem is with you service provider. Try the connection again later and if it persists then you should contact your ISP.
Step5
Error message "Host Unavailable," "Host Unknown," or "Network Connection Refused by Server" means the web server is down or busy, or the website has moved. Check the address that you have entered and try it again. If you still get this error message then the server the website is on is not functioning properly or the site has been moved.
Step6
If you see the message “Bad file request,” you may want to send a message to the site’s webmaster about the issue. This means the page should be available but for some reason it is not working correctly.
Decode and Resolve Common Computer Error Messages
Novice 
