Using latest release on El Capitan.
When I try to train as spam, I get the spinning beach ball on the Mac Mail app. All my other devices (iPhone and iPad) are unable to connect to my mail server (which is a Mac Server mail server). Sometimes control returns but the next one I try to train as spam the same thing happens. Eventually I have to force quit mail.
I’ve noticed that periodically my devices are unable to connect to the mail server.
When I removed the SpamSieve rule, all this behavior goes away. All my devices connect normally and no more beach ball.
How can I fix this and still get spam filtering?