ERR_NGROK_1420: Cannot delete IP Policy (POLICYID) because it is referenced by one or more IP Restrictions: (RESTRICTIONIDS) - ngrok documentation

What does ERR_NGROK_1420 mean?

ngrok returns ERR_NGROK_1420 with this message:

Cannot delete IP Policy (<POLICYID>) because it is referenced by one or more IP Restrictions: (<RESTRICTIONIDS>). Detach this IP Policy from all IP Restrictions before deleting it.

Where can I get more help with ERR_NGROK_1420?

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