If you received an error while making a request, visit Dedicated Datacenter Proxies documentation. Here you will find a dedicated section - Response codes - with all the error codes explained. You can also find them listed below.
407 Proxy Authentication Required - You are accessing proxy through 60000 port, but you have not provided authorization header, or your credentials are incorrect.
504 Gateway Timeout - Proxy server timed out. Waiting for a response from the target server. Usually about 60s.
503 Service Unavailable - Failed to connect to the target server. DNS failure to resolve the target server address.
401 Unauthorized - Incorrect credentials.
404 Not Found - The resource specified could not be found.
500 Internal Server Error - We had a problem with our server. Try again later.