DPY-6000: Listener refused connection

Summary:

Unable to connect to ATP DB via Python code

DPY-6005: cannot connect to database (CONNECTION_ID="").
DPY-6000: Listener refused connection. (Similar to ORA-12506)

Content (please ensure you mask any confidential information):

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):

import oracledb

connection = oracledb.connect(user="usr",password="pwd",dsn="(description= …") # the connection string copied from the cloud console