For six years we've been cultivating an email list with a morning newsletter sent daily.
For some reason, between 2015-2016, our email open rates started to nose-dive, going from roughly 30-40% average per day to 10-15%.
We don't know why, as we're using roughly the same tactics as we always did.
We use the self-hosted mail sending app 'Sendy' to send the mails and keep them short and to the point, delivering news about our subject to people who want to know about it (everyone opts into the list, we don't buy users or anything like that).
I need someone who can analyze our setup and identify what, if anything, we're doing wrong, and tell us how to get back on track and our open-rates up.