When I was developing my first test Face Book plugin I had the following errors that annoyed me for a few hours until I figured out my mistake. 404 Error: Error while loading page from [App name] Received HTTP error code 404 while loading http://www.mywebserver.com/facebookapp There are still a few kinks Facebook and the makers of test are trying to iron out. We appreciate your patience as we try to fix these issues. Your problem has been logged - if it persists, please come back in a few days. Thanks 405 Error: Error while loading page from [App name] Received HTTP error code 405 while loading http://www.mywebserver.com/facebookapp There are still a few kinks Facebook and the makers of test are trying to iron out. We appreciate your patience as we try to fix these issues. Your problem has been logged - if it persists, please come back in a few days. Thanks Solution I figured out that the solution for this error is simple as I used to fill in the Canvas Callback URL in facebook applic...