Nginx redirect config issue - nginx

Question

I have nginx bitnami container deployed in Openshift that serves my application. The issue that I am facing is that the redirect is not working. In the logs, there are no indications that the request is caught by a proxy_pass location block.
So. the idea is that a request to app.com/backend1/api/something should be forwarded to service1.com/backend1/api/something. The same goes for service2.
worker_processes 1;
events {
worker_connections 1024;
}
http {
upstream service1 {
server service1.com;
}
upstream service2 {
server service2.com;
}
server {
listen 8443 ssl;
listen [::]:8443 http2 ssl;
server_name app.com;
error_log /opt/bitnami/nginx/error.log debug;
ssl on;
ssl_certificate /etc/ssl/certs/nginx-selfsigned.crt;
ssl_certificate_key /etc/ssl/private/nginx-selfsigned.key;
ssl_dhparam /etc/ssl/certs/dhparam.pem;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_prefer_server_ciphers on;
add_header Strict-Transport-Security "max-age=31536000; includeSubDomains";
ssl_session_cache shared:SSL:10m;
ssl_session_timeout 10m;
keepalive_timeout 70;
include /opt/bitnami/nginx/conf/mime.types;
root /opt/bitnami/nginx/html;
location ~ ^/backend1/api/(.*)$ {
proxy_pass https://service1/backend1/api/$1;
proxy_http_version 1.1;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
}
location ~ ^/backend2/api/(.*)$ {
proxy_pass https://service2/backend2/api/$1;
proxy_http_version 1.1;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
}
location / {
try_files $uri /index.html;
}
}
}
I have also tried moving the order of the location blocks, as well as moving the root directive, but without success.
Any ideas on how to resolve this issue?