Nginx is trying open file instead of redirect to proxy

Hi I am using Nginx together with njs and have such location in my config Inside of njs file I am making POST request to API In this request I am getting body response as formdata converting it to JSON and making POST request to 3rd party with following error. *63 open() “/usr/share/nginx/html//tc/api/endpoint/book” failed (2: No such file or directory) while sending to client, client: 10.0.0.14, server: _, request: “POST /checkout/payment?key=val HTTP/1.1”, subrequest: “/tc/api/endpoint/book”, upstream: “https://11.100.216.19:443//book”, host: “proxy.eu-west-2.elb.amazonaws.com” This request should be proxied to 3rd party but looks like it trying to open file but not making redirect. This issue