How to connect laravel project in App Platform to Database Managed Cluster?

Hello everyone, I try to deploy a Laravel project in Digitalocean App platform but I have problems with database connections. My env variables are:

DB_HOST = ${db-cluster-name.DATABASE_URL}
DB_CONNECTION = mysql
DB_PORT = ${db-cluster-name.PORT}
DB_DATABASE = db_name
DB_USERNAME= db_username
DB_PASSWORD= db_password

When I try in DO console commands like:

php artisan migrate

I have the following errors:

In Connection.php line 671:
                                                                                                                                                        
  SQLSTATE[HY000] [2002] php_network_getaddresses: getaddrinfo failed: Name or service not known (SQL: select * from information_schema.tables where t  
  able_schema = circle_in_family and table_name = migrations and table_type = 'BASE TABLE')                                                             
                                                                                                                                                        

In Connector.php line 70:
                                                                                                  
  SQLSTATE[HY000] [2002] php_network_getaddresses: getaddrinfo failed: Name or service not known  
                                                                                                  

In Connector.php line 70:
                                                                                               
  PDO::__construct(): php_network_getaddresses: getaddrinfo failed: Name or service not known 

Any ideas?