currently trying to proxy to another port to serve up a shiny app. Followed this tutorial and adapted to return based on nginx documentation recommendations. It works..

    location /shiny/ {
      rewrite ^/shiny/(.*)$ /$1 break;
      proxy_pass http://localhost:3838;
      proxy_redirect / $scheme://$remote_addr/shiny/;
      proxy_http_version 1.1;
      proxy_set_header Upgrade $http_upgrade;
      proxy_set_header Connection "Upgrade";
      proxy_set_header    Host $remote_addr;
      proxy_read_timeout 20d;
      proxy_buffering off;
      return 301 $scheme://$remote_addr/shiny/;
    }

but if I try for a more complex path like below, it falls apart. What am I missing? I've tried making sure my regex works and it appears to.

    location /services/1234/service/shiny/ {
      rewrite ^/services/1234/service/shiny/(.*)$ /$1 break;
      proxy_pass http://localhost:3838;
      proxy_redirect / $scheme://$remote_addr/services/1234/service/shiny/;
      proxy_http_version 1.1;
      proxy_set_header Upgrade $http_upgrade;
      proxy_set_header Connection "Upgrade";
      proxy_set_header    Host $remote_addr;
      proxy_read_timeout 20d;
      proxy_buffering off;
      return 301 $scheme://$remote_addr/services/1234/service/shiny/;
    }