It need to being paired two site with "VMware vCloud Availability" in different locations.
We have:
Both sites: ESXi 6.7.0 / Build 151601 38
Both sites: vCenter Server Version: 6.7.0 / Build: 151299 73
Both sites: VMware vCloud Availability / 3.5.0.15038 129-0f0184b
One site: vCloud Director version: 10.0.0.154496 38
Other site: vCloud Director version: 9.1.0.119778 10
There are no networking issues between both locations.
Moderator: Moved to vCloud Director
This error typically is due to the endpoint configuration on the tunnel appliance and ensure it matches what's specified in the URL endpoint. Verify this is setup correctly between the Cloud Replication Manager and the Tunnel appliance.