Hi. My site is called Womanology and I was using Subscribe 2 without any problems until recently.
However, there was recently a worrying episode where somehow someone managed to register as an admin instead of a user (I wasn't even notified, I just noticed it). I removed them, changed a few settings, and installed SABRE to try to prevent similar things happening in future. (I've also recently updated my versions of WordPress and Subscribe2.)
And now when people try to subscribe, they don't get an email, and I don't get a notification of a new subscriber. Also, nothing appears in any column of the subscriber list. It just seems dead (although notifications of new posts still work, as does the test email). No more subscribers for me!
I do get that warning message about emails with non-matching domain names, but it was never a problem before. I've tried deactivating SABRE and messing around with my settings again, but to no avail.