Echo is in the nginx configuration but what happens if there is no output?

[nailsoul]

location / { echo "haha"; proxy_pass http://www.xxxxx.net; proxy_redirect off; proxy_set_header Host www.xxxxx.net; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; }

Access. log and error.log and HTTP response are not available. What should haha do to display?