Veeam infrastructure rpc server unavailable

[jvthree]

Veeam backup infrastructure rpc server unavailable vmware
or
Server Firewall blocking Add Server

I poked around and didn't find a thread on this so I am leaving this in case others have problems.

When trying to add a client server to the Backup Infrastructure Add Server fails with RPC error.

Here's how I think this came about:
Reinstalled vCenter & Veeam B&R on Utility server
After install couldn't add client server to Backup Infrastructure on some servers but not all. Add Server failed with RPC error; also couldn't add as proxy.
Backups & Replication worked fine.
If I turned off Firewall on client server Veeam B&R could detect the server and install. As soon as firewall was turned back on the server became unavailable.

http://www.veeam.com/kb1174
Tried this above but it broke the RPC and Internet. Removed the reg hack and restarted - fixed that.

Resolution:
Uninstalled agents and transport on client server, re-ran Add Server in Managed Servers on Utility server and VBnR was able to locate and install Agent and Transport.

I have read other threads with similar issues, some suggesting after update this occurs. Could be that Agent and Transport on Client are blocking ports or processes after upgrade or reinstall.