A 413 Request Entity Too Large error is a webserver’s code for:
"That's an enourmous thing you tried to send. I can't accept that."
A 413 Request Entity Too Large error occurs when a request made from a client is too large to be processed by the web server.
If the web server is setting a request limit, visitors may get a 413 Request Entity Too Large response.
An example request, that may cause this error would be if you were trying to upload a very large file to the server.