With using RELAY_URL=ws://127.0.0.1 in my .env: 

agent-1  | [2024-10-24T19:47:59.458397+00:00] agent.INFO: Client connecting to ws://127.0.0.1 [] []
agent-1  | PHP Fatal error:  Uncaught Amp\Socket\ConnectException: Connection to tcp://127.0.0.1:80 failed after 3 attempts; previous attempts: Connection to tcp://127.0.0.1:80 @ tcp://127.0.0.1:80 refused, Connection to tcp://127.0.0.1:80 @ tcp://127.0.0.1:80 refused in /app/vendor/amphp/socket/src/RetrySocketConnector.php:50