413 Request Entity Too Large

Checklist

• Have you pulled and found the error with jc21/nginx-proxy-manager:latest docker image? Yes

• Are you sure you're not using someone else's docker image? Yes

• If having problems with Lets Encrypt, have you made absolutely sure your site is accessible from outside of your network? Yes, but not related

Describe the bug
File uploads trigger 413 Request Entity Too Large
Setting the advanced config client_max_body_size 100m; takes no effect and the problem persists

To Reproduce
Steps to reproduce the behavior:

1. Upload a larger file on a website going thru the proxy, 413
2. Set an appropriate client_max_body_size
3. try to upload again
4. See a 413

Expected behavior
client_max_body_size would take effect and allow the upload as it does with regular nginx

Screenshots
If applicable, add screenshots to help explain your problem.

Start by reproducing the 413 with the jc21/nginx-proxy-manager:latest Docker image and a larger upload through a proxy host. Compare the advanced config containing client_max_body_size 100m with the generated Nginx configuration and verify that the setting is applied; done means the configured limit allows the upload without a 413.