Back to square one for a forum.
Esotalk is really nice – but the recaptcha plugin has disappeared from github, and no forum is viable without a registration captcha.
Flarum is the successor to Esotalk, but last time I tried it, maybe six months ago, I couldn’t get it working. It’s not production ready, even for open source values of production.
Have to remove the forum tab from the site for now.