Trouble deploying strapi 4 on Render

as error says you need to add “App keys” in config/server.js
but i would make config/env/production/server.js and then in it add something like this. As you will need or server automatically adds NODE_ENV=production

and for “App keys” you need to add 2 random strings (16 character long) env variable when deploying in my case A9_APP_KEYS= xyxyxyxyxyxyxyxy, yxyxyxyxyxyxyxyx

my server.js:

module.exports = ({ env }) => ({
  host: env('HOST', process.env.A4_HOST),
  port: env.int('PORT', process.env.A5_PORT),
  cron: {
    enabled: true,
    tasks: cronTasks,
  },
  url: env('APP_URL'),
	proxy: true,
  app: {
		keys: env.array('A9_APP_KEYS')
	}
});

but i would suggest you to move hosting to Railway as its cheaper, and you get 5$ free per month or 10$ if you verify with card. Im currently hosting there with postgres database and im estimated spending is 3$