title: CX_ORACLE TNS:listener does not currently know of service requested in connect descriptor
body: <p>I am trying to connect a database server from python using cx_oracle . I have constructed connection string as</p>
  
  <pre><code>dbconfig['schema']+"/"+dbconfig['password']+"@"+dbconfig["ip"]+"/"+dbconfig['sid']
  </code></pre>
  
  <p>where dbconfig is dictionary with necessary credentials for database connection</p>
  
  <p>I am able to connect to one of the server using VPN connection . But when I try to connect to one of the server in local network it displays "TNS:listener does not currently know of service requested in connect descriptor" error.</p>
  
  <p>I even modified tnsnames.ora file with appropriate sid even though it was not required in other case . After that, I was able to login using sqlplus . But had no luck with python code.</p>