ERR_NGROK_1930: Nameservers are not set up correctly for DOMAIN, expected WANT but got GOT - ngrok documentation

What does ERR_NGROK_1930 mean?

ngrok returns ERR_NGROK_1930 with this message:

Nameservers are not set up correctly for <DOMAIN>, expected <WANT> but got <GOT>

Where can I get more help with ERR_NGROK_1930?

Email support@ngrok.com and include the error code.