ER05015 error: The appliance machine [servername] doesn't install virtual machine tools or it is not in the virtual server.
A customer with a full system HA scenario moved their virtual platform host and virtual appliance host to another site and then stopped the scenario and updated the new IP addresses for these 2 hosts and now when they try to run the scenario they receive this error.
Customer did not update the new IP address for his ESX host in the scenario properties, he had only updated the IP address of the appliance host. We updated the virtual platform host IP on the properties tab for the replica under the 'virtual machine' section to resolve this error.
To get to this section in the left hand pane expand your scenario and click on the replica host, now in the right hand pane click on the properties tab and then expand virtual machine.