Where I would start is to see if your client has an ARP entry for your VIP when you try to ping or otherwise route traffic to it.
If you don't see an ARP entry for the VIP, it's possible your switch isn't forwarding multicast traffic.
The VIP by default uses a Multicast MAC and some switches may not forward this unless configured to do so.
See: Configuring Cisco Switch / Router to work with ClusterXL Multicast ARPs
I would also verify (using tcpdump) packets from the client are being received at the gateway.