Mezzio app works fine on built-in php server but gives error when run in docker container

Question

I've got a Mezzio application that works perfectly on built-in php server using compoer serve, however, when I try it in docker environment, it gives me following error.

Fatal error: Uncaught Laminas\View\Exception\RuntimeException: Laminas\View\Renderer\PhpRenderer::render: Unable to render template "error::error"; resolver could not resolve to a file in /var/www/portal/vendor/laminas/laminas-view/src/Renderer/PhpRenderer.php:492 Stack trace: #0 /var/www/portal/vendor/mezzio/mezzio-laminasviewrenderer/src/LaminasViewRenderer.php(232): Laminas\View\Renderer\PhpRenderer->render(NULL) #1 /var/www/portal/vendor/mezzio/mezzio-laminasviewrenderer/src/LaminasViewRenderer.php(221): Mezzio\LaminasView\LaminasViewRenderer->renderModel(Object(Laminas\View\Model\ViewModel), Object(Laminas\View\Renderer\PhpRenderer), Object(Laminas\View\Model\ViewModel)) #2 /var/www/portal/vendor/mezzio/mezzio-laminasviewrenderer/src/LaminasViewRenderer.php(138): Mezzio\LaminasView\LaminasViewRenderer->renderModel(Object(Laminas\View\Model\ViewModel), Object(Laminas\View\Renderer\PhpRenderer)) #3 /var/www/portal/vendor/mezzio/mezzio/src/Response/ErrorResponseGeneratorTrait.php(61): Mezzio\LaminasView\LaminasViewRende in /var/www/portal/vendor/laminas/laminas-view/src/Renderer/PhpRenderer.php on line 492

NGINX proxy (nginx.conf)

user root;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;

events {
    worker_connections 1024;
}

http {

    upstream nginx-web {
        server web:8110;
    }

    upstream nginx-portal {
        server portal:8115;
    }

    upstream nginx-api {
        server api:8120;
    }

    proxy_set_header   Host $host;
    proxy_set_header   X-Real-IP $remote_addr;
    proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header   X-Forwarded-Host $server_name;

    server {
        listen 80;
        server_name proxy;

        location /web {
            proxy_pass          http://nginx-web;
        }

        location /portal {
            proxy_pass          http://nginx-portal;
        }

        location /api {
            proxy_pass          http://nginx-api;
        }
    }
}

Server Block (default.conf) portal

server {
    listen 8110;
    root /var/www/portal/public;
    server_name proxy;

    location / {
        try_files $uri $uri/ /index.php$is_args$args;
        index index.php;
    }

    location ~ ^/.+\.php(/|$) {
        fastcgi_pass  php:9000;
        fastcgi_index index.php;
        include       fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    }
}

docker-compose.yml

version: "3.9"

services:
  db:
    container_name: db
    image: mysql:5.7
    ports:
      - "3306:3306"
    volumes:
      - "${PROJECT_ROOT}/db:/var/lib/mysql"
      - ./conf/db/my.cnf:/etc/mysql/conf.d/my.cnf:ro
    env_file:
      - .env
    networks:
      - backend

  proxy:
    container_name: proxy
    image: nginx:mainline-alpine
    volumes:
      - ./conf/proxy/nginx.conf:/etc/nginx/nginx.conf:ro
    ports:
      - "80:80"
      - "8110:8110"
#      - "8115:8115"      
      - "8120:8120"
    depends_on:
      - web
      - portal
      - api
    networks:
      - backend

  web:
    container_name: web
    image: nginx:mainline-alpine
    volumes:
      - "${PROJECT_ROOT}/web:/var/www/web"
      - ./conf/web/default.conf:/etc/nginx/conf.d/default.conf:ro
    depends_on:
      - php
    networks:
      - backend

  portal:
    container_name: portal
    image: nginx:mainline-alpine
    volumes:
      - "${PROJECT_ROOT}/portal:/var/www/portal"
      - ./conf/portal/default.conf:/etc/nginx/conf.d/default.conf:ro
    depends_on:
      - db
      - php
    port:
      - "8115:8115"
    networks:
      - backend

  api:
    container_name: api
    image: nginx:mainline-alpine
    volumes:
      - "${PROJECT_ROOT}/api:/var/www/api"
      - ./conf/api/default.conf:/etc/nginx/conf.d/default.conf:ro
    depends_on:
      - php
    networks:
      - backend

  php:
    container_name: php
    image: maciejslawik/php-fpm-xdebug:latest
    ports:
      - "9000:9000"
    volumes:
      - "${PROJECT_ROOT}/web:/var/www/web"
      - "${PROJECT_ROOT}/portal:/var/www/portal"
      - "${PROJECT_ROOT}/api:/var/www/api"
      - ./conf/php/docker-php-ext-xdebug.ini:/usr/local/etc/php/conf.d/docker-php-ext-xdebug.ini:ro
    networks:
      - backend

  composer:
    container_name: composer
    image: composer:2
    restart: "no"
    command: install
    volumes:
      - "${PROJECT_ROOT}/composer:/app"
      - ./composer/composer.json:/app/composer.json
    networks:
      - backend

  phinx:
    container_name: phinx
    image: vegbrasil/phinx:latest
    volumes:
      - "${PROJECT_ROOT}/migrations/database/migrations:/app/database/migrations"
      - "${PROJECT_ROOT}/migrations/database/seeds:/app/database/seeds"
      - ./conf/phinx/phinx.php:/app/phinx.php:ro
    env_file:
      - .env
    depends_on:
      - db
    restart: "no"
    command: "status"
    environment:
      - TESTS_PHINX_DB_ADAPTER_MYSQL_HOST=db
    networks:
      - backend

  schemaspy:
    container_name: schemaspy
    image: schemaspy/schemaspy:latest
    volumes:
      - "${PROJECT_ROOT}/schemaspy/output:/output"
      - ./conf/schemaspy/schemaspy.properties:/schemaspy.properties:ro
    restart: "no"
    depends_on:
      - db
    networks:
      - backend

networks:
  backend:

Update I've tried to xdebug the issue. What I've figured out is that .phtml template file is not being resolved by PhpRenderer.php. Also I'm accessing it with url http://web.local:8115/dashboard however, ideally, I'd like to access it as http://web.local/portal/dashboard.

Suggestions Could it be that default.conf file is processing only .php files and not .phtml files, however, I doubt it as the issue is, there's a line $file->isReadable() isn't able to process the file whereas I've verified that the file does exist. i.e. summary.phtml.

The permission for this file is also fine.

drwxrwxrwx 1 root root 4096 Oct 31 07:57 .
drwxrwxrwx 1 root root 4096 Oct 31 07:57 ..
-rwxrwxrwx 1 root root  197 Oct 31 07:57 summary.phtml