If you’ve subscribed yourself to https://status.mendix.com/ you can simply unsubscribe there from what i know.

You could also be receiving messages because you are the app contact or the technical contact for your application. Which is found if you go to https://sprintr.home.mendix.com/index.html select your app and then check the General tab.

You can also unsubscribe from environment specific messages which is also found at Sprintr, but by going to the Alerts tab.