The below property for database connection was commented out in the site.properties file:
Due to which it was throwing error in registry.log:
2020-05-14 14:52:57,230Z (09:52) [qtp1117319688-86] ERROR net.sf.jasperreports.web.
Release : 10.5
Component : CA Service Virtualization
Uncommented property lisadb.pool.common.driverClass=oracle.jdbc.driver.OracleDriver in the site.properties file and re-started Registry. The issue gets resolved and reports are opening fine now.