No, using Inbox should be just as safe as using Gmail. I don't recognize that exact notification text, but I suspect you're seeing the notification mentioned h

No, using Inbox should be just as safe as using Gmail. I don't recognize that exact notification text, but I suspect you're seeing the notification mentioned here (https://support.google.com/a/answer/6260879 https://support.google.com/a/answer/6260879). As noted on that page, this is triggered by use of password-based auth (rather than OAuth). Is it possible you're signed into your account from Apple Mail using just a password?