I'm having DNS issues with my Hap AC2. It experienced a sudden power loss, and when I rebooted the router, DNS stops working entirely.

I'm using a PPPoE connection from my ISP with their DNS servers. I ticked the Peer DNS option, so in the Dynamic servers my ISP's DNS server shows up, and I'm still connected to the internet.
However, the local DNS services is down - I can't resolve domain names from the router itself. But I can resolve domain names from PCs and other devices. But any device that uses the router for its DNS cannot resolve anything.

I've tried:

• Putting my ISP DNS server onto the "Servers" box in IP > DNS
  Rebooting cleanly
  Power cycling
  Restoring backup

Those don't work. Any ideas on what to check?

Is "allow remote requests" enabled under IP DNS?

It's disabled. But it makes no difference enabled/disabled.

Do the host names/website addresses show up in your DNS cache?

No, the only entries were the router's address and the reverse lookup address for the router.

Well there were no solutions but to do a netinstall and reinstall routeros. I guess the power outage corrupted something.