Cannot perform JDBC test with Visual Composer

Folks,

I am trying to test JDBC connection with Visual Composer. I use the URL http://<hostname>.<domainname>:<port>/TestJDBC_Web/TestJDBCPage.jsp

and I try to test "JDBC Page" and click Check Connections, it is gives me an error

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500   Internal Server Error

Test JDBC Page

Error!

Could not connect to database. Connection is inactive or does not support JDBC.

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I try to test connection from the portal and it gives the error "Connection failed. Make sure user mapping is set correctly and all connection properties are correct"

I have followed the SAP Guides "How to configure BI JDBC System for Visual Composer.pdf" and "How Toresolve visual composer issues.pdf", and everything looks proper. But still I get this error.

Kindly help me in this issue. Any kind of help with be rewarded with points.

Thanks.