When uploading a file in multipart/form-data to the server where the Nginx proxy is located, do the files disappear?

Question

Nginx

Hi all.
I have a node.js application that takes images, compresses them, and saves them to a public directory. Locally everything works fine. I send data via multipart/form-data, and in the application I use express-fileuploaded.
You need to bring this module to the server. At the front is NGINX. And here is the dilemma. On the server, there is a files parameter in request, but it is null. The files are lost somewhere. What could be the reason?