(Last login: 08/26/2018)
Error 503 Service Unavailable is a failure to access the website. Then, on the web browser will display the message "Error 503 Service Unavailable"
The cause of the 503 error is mainly from the web server due to:
Web server is temporarily unavailable
Web server is busy
The server is overloaded
Sometimes it is possible that your server is suffering from DDOS.