How do I troubleshoot a nginx 413 error?

I'm getting a 413 error on my laravel forge site using nginx.

I updated php.ini for cli and ftp to 1000m and updated my nginx config for client_max_body_size = 1000m. Still getting that 413. The file I'm trying to upload is 6 megabytes.

Is there a log file that I can peruse that would help me troubleshoot that further? How should I better troubleshoot this error?