After installing Veeam at a clients site and setting it up to replicate a 2 host cluster and san to a single host with storage it tested OK in the test environment. The servers where then IP`d and put into the correct sub net with the relevant gateways etc.
Then the replication job was made live and left to run over night. Next morning I checked only to find this error below.
Now I knew that IP`s had been changed so I tested the following.
From the Veeam server.
Pinged its gateway – OK.
Pinged its DNS servers – OK.
Pinged the source VM hosts – FAIL
Pinged the storage – OK.
The the Veeam side failed on pinging the source hosts, I checked all my local settings which were ok. I went onto my hosts and checked the Local IP settings. It turns out that there was incorrect setting for the hosts gateway. I changed accordingly and the pings were fine.The hosts could not talk back to the Veeam server correctley. Then I set the replication away and it completed successfully.
The point of this post is the error:client error: NFC Storage connection is unavailable. Failed To Create NFC Downstream is generally an IP misconfiguration error or a communications error. So look there first and test the simple tings like pings.