Request Entity Too Large (php Error 413)

I’m working with the free version of the WP File Manager. We have it installed in a multisite configuration in our intranet.

I’ve verified that I have the php settings for the server set (as follows):
memory_limit=256M
upload_max_filesize=512M
post_max_size=256M

I’ve verified that the free version of the plugin appears to have the max file size set at 200Mb.

However, when I try to upload a file (.pdf) that is 1.2Mb in size, I’m getting the “Entity Too Large” error.

Is there another place I need to look regarding settings to allow this to work?

Thank you.