Diane,
As you are in IS 8.2.2, there is a known fix for this. Verify if you have correct fix level and if problem exists.
If you are already in latest fix or have Fix12 already installed, and still have this problem, in extended settings, set the mail.debug=true to watt.config.systemProperties, restart your server and collect more details to debug further.
Regards
Senthil
#Integration-Server-and-ESB#webMethods