SMTP not working after upgrade

[Lee Anne Pedersen]

After upgrading from Confluence 3.5.5 to 5.1.5 and moving from a Windows 2003 server to a Windows 2008 server this weekend, SMTP email no longer works. I get the following error when trying to send a test message:

An error has occurred with sending the test email. If your mail server requires authentication, please ensure that TLS or SSL is enabled on your server for the specific mailbox. If your mail server allows anonymous connection, please remove the username and password from the configuration and try again.

com.atlassian.mail.MailException: javax.mail.AuthenticationFailedException: No authentication mechansims supported by both server and client
	at com.atlassian.mail.server.impl.SMTPMailServerImpl.send(SMTPMailServerImpl.java:193)
[truncated]

At the suggestion of our Exchange admin, I removed the username and password that had, until the upgrade, worked fine for authentication. He said anonymous would work internally. Then I got this error:

An error has occurred with sending the test email:
com.atlassian.mail.MailException: javax.mail.AuthenticationFailedException: failed to connect, no user name specified?
	at com.atlassian.mail.server.impl.SMTPMailServerImpl.send(SMTPMailServerImpl.java:193)
	at com.atlassian.confluence.jmx.JmxSMTPMailServer.send(JmxSMTPMailServer.java:80)
	at com.atlassian.confluence.admin.actions.mail.SendTestEmailAction.execute(SendTestEmailAction.java:58)
[truncated]

I thought McAfee might be blocking the sending, but I confirmed it was configured to warn only, not block. I would appreciate any suggestions.

[Lee Anne Pedersen · Accepted solution]

After discovering this issue (https://jira.atlassian.com/browse/CONF-29000), I created a new SMTP configuration from scratch and was able to get anonymous sending to work.