Your log data shows failures due to traffic connectivity or firewall rules.
Jul 31, 2013 21:37:14 +0000 NewRelic 10 INFO: Failed to connect to collector.newrelic.com.:443 for My Application:java.net. ConnectException: Connection refused:connect
Jul 31, 2013 21:37:14 +0000 NewRelic 40 INFO: The data collector is temporarily unavailable. This can happen periodically. In the event that availability of our servers is not restored after a period of time, then please report this to New Relic. java.net.SocketException: Connection reset
New Relic's Java agent attempts to connect about once a minute. You can identify possible connection failures by searching for lines like this and checking if they are happening every minute.
The agent can cache a significant amount of metric data when it cannot connect. Even if the outage lasts a few minutes, in general, this will not result in any loss of information in the New Relic APM UI.
Intermittent connection issues can occasionally cause many of these messages in a short time. If this occurs only once every few days, and all your data is present, you can safely ignore these messages.
If failures occur every minute for more than a few minutes, then the agent is not able to connect at all, and no data is being reported. Ensure that New Relic is not experiencing availability problems. Check New Relic's status at http://status.newrelic.com. If New Relic is not reporting any issues, gather information to troubleshoot the issue.
Occasional failures to connect to the New Relic collector should not be a cause for concern. These failures should not affect the performance metrics available in your New Relic user interface.
Despite the log text, this error generally is caused by a failure of connectivity or firewalled traffic rather than the New Relic collector actually being unavailable. New Relic is working to improve the information logged here. For more information, see the list of IP ranges used by all of New Relic's services.