We’ve been having a very odd issue with new Windows 2019 server running Hyper-V in that some of them will fail to enable Replication for VMs. You get to the very end and and click the last button to start and the Replica VM is created on the other system and all the place holder files exist but then it errors with an message about not being able to send the initial replica. We’ve tried all kinds of suggestions on the web related to ACLs and firewall configuration but none of them worked. I found a solution though. If you make a Checkpoint of the system having issues and then delete the Checkpoint after its completed you can now enable Replication. It seems the issue resides on the system where the VM currently lives and not the location it’s going to and forcing a Checkpoint corrects whatever is going wrong during Replication configuration.