START page and then just under your name is a link to your Account/Email preferences.
Otherwise you will need to go to each team and visit the threads you want to receive notifications on and make sure the box below your reply is checked. No other easy way that I am aware of. 90 days ago
Sometimes the email choice gets disconnected or you accidentally click the "send me an email when" box right under a message. Once you revisit the threads you should be back on track. If not, check your email settings on Spark. 90 days ago