Hello, I’m running a self-hosted Ghost, currency in version 5.26. I have done some social media post about it and the feedback was that visitors wanting to subscribe were shown an error message while some of them managed to subscribe.
Upgrading is unlikely to fix it, but there are new features you might want anyway.
Your email is probably misconfigured. Post more information about your installation, including the package.json (minus passwords) if you’d like help.
Some links specifically for transactional email (which is your problem):