Check condition in Symmetrix

Hi all,

I have a Symmetrix VMAX 20K and I have the following problem over one iSCSI port. Every 300 seconds, my server (ESXi) sends a SCSI message "Test Unit Ready LUN". VMAX used to reply with the SCSI message "Test Unit Ready"; however, since some days ago, in one specific iSCSI port, I get the message: "Check Condition". My server then sends the test message again but it receives the same reply. After that the connection is restarted several times .

Do you know what can be the reason for the "Check Condition" in just one of the ports? Where could I get more infor from VMAX?

Thanks!