Issue:
While installing RU patches it is failing at DB screen with error "Cannot connect to Oracle server. Check the details provided" and in install.log gives ERROR [AWT-EventQueue-0] [MDBValidator] SU2048
Release : 17.3
Issue is due to Oracle DB connectivity.
The current problem occurs while validating the connection via the Oracle JDBC driver. Need to validate Oracle connectivity as per below KB:
https://knowledge.broadcom.com/external/article/221075/testing-oracle-jdbc-connection-with-jdbc.html
If the test is not successful then this needs to be solved by Oracle DBA, once it's solved and the connection is successful can proceed with patch installation.