IIS 7 – How to Resolve Error HTTPs 413: Request Entity Too Large

couple of days ago, I came across an issue where when user leave the web page idle and try to upload a file using JQuery-FileUpload; user was getting error 413. and sometimes users were getting “The page was not displayed because the request entity is too large.” error.

I increased the uploadReadAheadSize  value on IIS and that was enough to fix the issue; I did the followings:

1. Launch “Internet Information Services (IIS) Manager”
2. Select the site that you are hosting your web application under it.
3. In the Features section, double click “Configuration Editor”
4. Under “Section” select: system.webServer  then serverRuntime
5. Modify the “uploadReadAheadSize” section to be like 20MB (the value there is in Bytes)
6. Click Apply

The error is happening as during renegotiation step between your web browser and the IIS Server; the entity should be preloaded using SSL. and result is being larger than the default value which is ~49K