DockerCon2017: Javadebugging : Database Connection failing

[BXK20]

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Upon usersignup then signup then submit then confirm with Yes, I get the below error:
Request processing failed; nested exception is org.springframework.dao.DataAccessResourceFailureException: Could not open connection; nested exception is org.hibernate.exception.JDBCConnectionException: Could not open connection

Any resolution steps for this ?
Thanks