This error typically indicates a communication or configuration issue preventing the vSphere Replication appliance from interacting correctly with vCenter Server.
vSphere Replication 8.7
VMware Site Recovery Manager 8.7
The Broadcom product interoperability matrix indicates that VMware Site Recovery Manager & VMware vSphere Replication 8.7 are incompatible with VMware vCenter 8.0 Update 3g
To fix this issue, upgrade vSphere Replication & VMware Live Site Recovery to a supported version & reconfigure the appliances to register with vCenter.