The agent logs are placed on source machine (i.e. machine to be converted) and this log will help us to understand where the problem is.
I can't say why you can't see the problem, but from my (remote) perspective, there is no chance to help, at least, without log files.
if it helps anyone, I had the same issue. for me the fix was the source machine could not resolve the names of the esxi hosts. manually adding them and the vcenter IP's to the hosts file fixed it.