"Service Temporarily Unavailable" error when trying to log in to Satellite web UI

Issue

• getting 503 Service temporarily unavailable when trying to open /rhn/Login.do web page on the host
• the Satellite login web page does not open

• errors in Tomcat log /var/log/tomcat5/catalina.out like the following:

  WARNING: com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@75307530 -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of a
  llowed acquisition attempts (30).
  2011-06-29 11:00:27,387 [TP-Processor3] WARN  org.hibernate.util.JDBCExceptionReporter - SQL Error: 0, SQLState: null
  2011-06-29 11:00:27,387 [TP-Processor3] ERROR org.hibernate.util.JDBCExceptionReporter - Connections could not be acquired from the underlying database!