Cannot Send Email Due to 'javax.mail.NoSuchProviderException' SMTP Error
When Confluence tries to send mail, a "javax.mail.NoSuchProviderException: smtp" error is thrown.
Two different versions of Sun's Javamail libraries are in the application classpath. When Confluence tries to send an email, Java gets confused as to which version of the library it should be using.
If (and only if) you are encountering this error, remove the
activation-1.x.jar files from the
confluence/WEB-INF/lib directory of your Confluence installation, then restart Confluence.