2nd ESX can't connect to storage group via iSCSI

Hi.

I'm trying to connect 2 esx 3.5 servers to a Clarion SAN via iSCSI. The first server connected with no problems, I added it to the "ESX" storage group, did a rescan and it can see all the LUNs.

For some reason the second esx server can't be added to the ESX storage group. In Navishphere the second esx server doesn't show as an available host when trying to add it to the ESX storage group. I can add it to other storage groups, but not the one that has the first esx server connected.

Any ideas what I could be doing wrong?