To resolve this issue, the placeholder VMs need to be restored.
Step 1:
Navigate to the destination site(recovery site) vCenter.
Locate the inaccessible VMs and remove them from the inventory.
Step 2:
At the source site(protected site), Navigate to the Site Recovery Plugin UI.
Select the Site pairing and then navigate to Protection Groups.
Select the relevant protection group from the left pane.
Within the right pane, select the VM that shows a Protection Status of 'Placeholder VM not found'
At the top of the VM list, select 'RESTORE ALL PLACEHOLDER VMS'
Confirm that the placeholder VMs are no longer inaccessible after the operation completes.