The Web Proxy service detected that the upstream proxy "<IP address>" is now available. If you were able to work around the upstream proxy server no further action is necessary. If you changed the configuration of the primary route to the upstream ISA Server you might want to change it back.
Build a great reporting interface using Splunk, one of the leaders in the Security Information and Event Management (SIEM) field, linking the collected Windows events to www.eventid.net.
Obtain enhanced visibility into Cisco ASA firewall logs using the free Firegen for Cisco ASA Splunk App. Take advantage of dashboards built to optimize the threat analysis process.