Note: VeeamDeploySvc, Veeam Deployment Service, and Veeam Installer Service are all names for the same service.
When Veeam Backup & Replication attempts to interact with a Windows machine, it will first attempt to contact the Veeam Deployment Service on its default port of 6160. If that fails, it will then connect to the Windows machine via RPC and check if the VeeamDeploySvc is present, and if present, attempt to start the service. If the service is not present, Veeam Backup & Replication will install the Veeam Deployment Service and initiate a connection to that service over port 6160.
The errors discussed in this article occur because the VeeamDeploySvc, also known as Veeam Installer Service, is detected as being present but cannot be started due to an OS-level issue.