PowerVault MD3000i - Cluster unable to access CSV - iSCSI problem?

Hello,

We have a 3 node cluster with iSCSI links to our PowerVault MD3000i to provide a CSV which is shared between all 3 nodes. Unfortunately after some routine maintenance where the servers were restarted this CSV (\\Server\c$\ClusterStorage) is no longer accessible and when trying to access the process hangs in explorer. 

When running Get-ClusterSharedVolumeState the cluster shared volume stateinfo shows as: paused

In Event Viewer for each server there are multiple entries for: Event 5142: Failover Clustering. Cluster Shared Volume 'Production' ('SAN-LUN') is no longer accessible from this cluster node because of error '(1460)'. Please troubleshoot this node's connectivity to the storage device and network connectivity.

When searching online for this error, there are a few results for completing the following which I've confirmed is ok:

Review each cluster node and verify the following protocols are enabled the network adapters available for Cluster use:

• Client for Microsoft Networks
• File and Printer Sharing for Microsoft Networks

The LUN can be mounted directly to one node which then gives access to the data, but when changing it back to a CSV this breaks access immediately.

I suspect this is likely a problem with the iSCSI connections for the cluster to the PowerVault MD3000i. But with my limited knowledge on clustering and troubleshooting iSCSI connection issues I'm unsure on what to try next. 

Any help would be much appreciated. If any further information is needed just let me know.

Thanks

Update:

On the Event Logs for the SAN I can see that there are multiple entries for each of the affected nodes with the following errors:

iSCSI Session terminated unexpectedly

iSCSI connection terminated unexpectedly

Host Topology - Initiator registration failed