After you restart vCenter Server, when you use vSphere Replication, reprotect operations sometimes fail.

After you restart vCenter Server, when you use vSphere Replication, reprotect operations fail with the error

Error - Unable to reverse replication for the virtual machine
	 'virtual_machine'. The session is not authenticated.

After vCenter Server restarts, it fails to refresh some sessions that Site Recovery Manager uses to communicate with vSphere Replication and causes reprotect to fail.

Restart the Site Recovery Manager services on both of the sites.