Our site is setup to access through a CDN.  

Wwhen wffm Form is submitted with image sizes of 3MB, it returns "413 Request Entity Too Large"  

I have seen this error suggested as file upload limit in CDN on online documentation. But our hosting provider suggeste it is due to too much information on PayLoad headers from wffm request, and suggest us to try to trim the headers on form submit request.

i.e. 

[![enter image description here][1]][1]


  [1]: https://i.sstatic.net/5YgN9.png


Any help on this is highly appreciated..