Connect is not available, request timeout after 30000ms.

I have upgarded my PostgreSQL database from 10 to 11 version using pg_dump method.

That database is used by two apps.

1. A   (most of the transaction are SELECT AND INSERT)

2. B   ( most of the transaction UPDATE AND DELETE)

After the upgarde I am facing *error:connection is not available, request timeout after 3000ms* with app B whereas app A is working fine with same database..

I have upgarded my JDBC driver with lastest driver to fix this issue but no luck.

Thanks for advance help.

Regards,

Pawan