Ha, no, that was a far more mundane issue. The CMS I'm using requires double opt-in to subscribe, meaning you need to enter your email address and click the confirmation link.
It also apparently requires double email configuration, meaning it has two places where you can configure your mailer. I had only set it up in one place, meaning the confirmations never got sent.
It also apparently requires double email configuration, meaning it has two places where you can configure your mailer. I had only set it up in one place, meaning the confirmations never got sent.
Bit of a facepalm moment.