The application writes the errors with following codes when something fails when trying to fetch the given URL.
E10 - Invalid URL
The given URL is invalid. For example:http://example.com:bad-port/
E20 - Invalid Domain
The URL has non existant domain.
E21 - DNS Timeout
The hostname couldn’t be resolved within config_dns_timeout seconds.
E30 - Connection Refused
Connection refused by the server.
E31 - Connect Timeout
Connection couldn’t be established within config_connect_timeout seconds.
E32 - Initial Data Timeout
Initial data (HTTP headers) couldn’t be obtained within config_initial_data_timeout seconds.
E33 - Read Timeout
When reading data from the remote server, no data was received for config_read_timeout seconds.
E34 - Connection Dropped
The remote server dropped the connection before all the data was received.
E39 - Unexpected Connection Error
Unexpected connection error when receiving data from the remote server.
E40 - Response Too Big
The response length is bigger than config_max_response_size bytes.
E41 - Request Took Too Long
The request was not completed within config_max_request_time seconds.
In all these cases, the application responds back with status 200 OK with a record contain status 302 Bad Gateway.