After upgrading vCenter (VCSA) to 6.0 U3 and upgrading the vSphere Replication Appliance to 6.1.2 the plugin in vCenter stops working. Follow this KB:
https://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2149560
And this KB to enable SSH (for those who are unfamiliar with how to enable SSH in a *nix environment):
https://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2112307