Thanks to everyone who helped. As soon as I saw the worker log I was able to see that there was a DNS issue. The machine I was trying to convert was its own, DC and its own DNS server. Once the connection was made back to my vCenter server, my vCenter server passed the FQDN of the EXSi host, which was unresolvable.
I then put in a conditional forwarder for the DNS domain necessary and this resolved the issue.