Wordpress in Appengine

[centrumX Online]

Hi, 

I have an issue about connecting the cloud sql database (second generation).  

The error connection said:  we can’t contact the database server at :/cloudsql/projectid:us-central1:myinstance. 

I defined in wp-config.php:

define('DB_HOST', ':/cloudsql/projectid:us-central1:myinstance');
   /** The name of the database for WordPress */
   define('DB_NAME', 'tutorialdb');
   /** MySQL database username */
   define('DB_USER', 'user');
   /** MySQL database password */
   define('DB_PASSWORD', 'passworduser');

The appengine application and cloud sql are in the same project, i forgot to configure something ? 

I hope you help with these issue. 

Thanks.

[Kenworth (Google Cloud Platform)]

Out of curiosity, is your project-id literally is "projectid" and your instance "myinstance"? If not please email privately both project-id and the name of the instance you are trying to establish connection. Include sanitized relevant logs, if any.