I followed this excellent guide to installing pihole on routerOS https://www.youtube.com/watch?v=UMcJs4oyHDk&t=8s

The DNS service resolves (although, unlike the tutorial, I had to enable Allow Remote Requests for anything to be resolved) and I can access the pihole admin pages, but it doesn't block any ads, as far as I can tell. It also refuses to do a gravity update, claiming that the DNS cannot be resolved.

I can browse away, but it clearly doesn't work.

How can I fix this?