Hyper-V Virtual Machine Connection keeps interrupted

[Miho Rosenberg]

When I connect to any VMs from Hyper-V Manager (not RDP), the connection fails every minute.

I get the error message "The connection to the virtual machine was lost. This can occur when a virtual machine stops unexpectedly, or when network problems occur...." 

This happens against all VMs running on this particular Hyper-V host. When I run the same VMs on a different host, it won't happen.

I can ping VMs even the error message pops up and it won't happens when I RDP VMs.

So I knew this is not real network connection issue.  

I believe it started after I set up Microsoft iSCSI initiator on this host machine.

The host machine is a desktop (HP p6330f) running Windows 2008 R2 SP1 Datacenter.

This is a test machine and has only one NIC. I needed to connect to SAN (HP MSA2324i), so I changed an IP to a SAN subnet and switched back to LAN subnet IP.

I checked  Event Viewer and saw a bunch of errors from iScsiPrt (Event ID: 52, Initiator Service failed to respond in time to a request to configure IPSec resources for an iSCSI).

I connected SAN again and disconnected the connection with the target from iSCSI initiator. Also I stopped MS iSCSI service.

Since then the above error message stopped being generated but VM connection still disconnected.

This is not a major problem since VMs still run. It's just annoying.

Please let me know how to fix this annoyance.

Thanks in advance!