“Some of the selected virtual machines are not in a valid state for replication."
"The replication of virtual machines encrypted with Native Key Provider requires Native Key Provider support. Native Key Provider support is not available for this VM.”
vSphere Replication 8.x
vSphere Replication 9.x
The Native Key Provider IDs between the source and target vSphere environments will be different, or the Native Key Provider will be missing on the target vCenter Server.
This will ensure that both vCenter environments share the same Key Provider ID and encryption key set, which is required for encrypted VM replication.
For more details refer : Replicating Encrypted Virtual Machines