After upgrading a client's Veeam solution to version 7 patch 4 I came across this error message for the replication jobs that were set up and it had me a little confused:
Processing configuration Error: Client error: NFC storage connection is unavailable. Storage: [stg:datastore-22,nfchost:host-21,conn:188.8.131.52]. Storage display name: [Temp].
Failed to create NFC download stream. NFC path: [nfc://conn:184.108.40.206,nfchost:host-21,stg:datastore-22@Server_replica/Server.vmx].
There is a knowledge base article on Veeam's website regarding this - http://www.veeam.com/kb1198 but given nothing had changed regarding ports opening/closing etc I was sceptical that this was the root cause. Especially since the replication jobs had worked an hour earlier, before the patch was applied.
After much head scratching and restarting of servers etc I found the resolution to the issue. Within the VMware vSphere client there is an option to rescan the storage attached to the host to help pick up new volumes, changes, etc, once I ran that on the host that the backup storage is attached to the replica jobs completed successfully!!
Am still unsure as to why the error occurred or why that fixed the issue but it did, one worth remembering!!