In the docs on replication there is a lot of talk about how the data is moved and proxies that are being used, but a small detail that is missing is that the B&R Server should be able to talk to both source and target vCenters & Hosts. I often see less experienced colleagues struggling to get replication working between vCenters of WAN, just because the docs don't clearly state that the B&R Server should see them, they all think that the proxies take care of the management communication. Which, by the way, would be great if proxies could handle that as well. https://helpcenter.veeam.com/backup/vsphere/offsite_replication.html
In the image, you see a line going pass all components, which probably is the indication that the B&R should be able to connect to all components. But a little more clarification would be welcome.