Unable to get connection, DataSource invalid - Netbeans, MySQL

Unable to get connection, DataSource invalid - Netbeans, MySQL

I'm following the tutorial of Netbeans site:
https://netbeans.org/kb/docs/web/mysql-webapp.html
everything was working fine until this step: Implementing JSTL code STEP 4
where the list should be displayed I get the following error:
javax.servlet.ServletException: javax.servlet.jsp.JspException:
Unable to get connection, DataSource invalid: "java.sql.SQLException:
Error in allocating a connection. Cause: Connection could not be allocated
because: java.net.ConnectException : Error connecting to server localhost
on port 1527 with message Connection refused."
root cause
javax.servlet.jsp.JspException: Unable to get connection, DataSource
invalid: "java.sql.SQLException: Error in allocating a connection. Cause:
Connection could not be allocated because: java.net.ConnectException :
Error connecting to server localhost on port 1527 with message
Connection refused."
note The full stack traces of the exception and its root causes are
available in the GlassFish Server Open Source Edition 4.0 logs.
I suppose netbeans still tries to connect to the Derby DB. How can i
change it to MySQL DB? I am using Java EE7, MySQL, Netbeans, Glassfish 7