Can't Connect to ISCSI Target from Win 2008 Svr R2

[help-net]

Hi, I have been having issues to connect to a readynas 2100 Iscsi targets from Win2008 servers. Everthing was working fine since long time ago and suddenly I cannot connect from the MS ISCSI initiator every time I tried to connect to the target it gives me a " Log on to target X service Unavailable " error. Targets are open , no CHAPS or any security for authentication. I restarted the Nas, installed latest Radiator firmware, restarted the Microsoft ISCSI initiator service, the ISCSI service ( TCP-in ) firewall rule is enabled. Also restarted the servers a couple of time and nothing my friend. is basically frustrating because from a 2003 server initiator everything works fine, connect and disconnect perfectly.

Any idea what could be the problem ?

thanks.