Either the server is configured as an ISATAP router or no IPv6 addresses were detected on the internal adapter of the server. ...

Either the server is configured as an ISATAP router or no IPv6 addresses were detected on the internal adapter of the server. This is not supported in a cluster configured to use an external load balancer. Either deploy IPv6 in the internal network, or deploy an external ISATAP router, and configure IPv6 connectivity between the router and the Remote Access server.