This error message comes from an incorrect DNS configuration. I think it was because my DNS was pointing to my ISP’s DNS server (techncally, to my router, which pointed to my ISP).
By configuring my domain controller (DC) with DNS, which in turn forwarded requests to the ISP, and then pointing all DNS to the DC, it seemed to resolve the issue. To get the DC to rebuild the DNS, run dcdiag /fix from a command prompt and/or restart the netlogon service.