[Nginx] upstream prematurely closed connection while reading response header from upstream 오류

Spring boot 서버 파일 업로드 적용 후 Nginx 배포 시

upstream prematurely closed connection while reading response header from upstream,

오류가 발생했다.

nginx.conf에 proxy timeout 설정 추가

참고 :
https://stackoverflow.com/questions/36488688/nginx-upstream-prematurely-closed-connection-while-reading-response-header-from