d-thinker.org mx is not responsive

[amoners]

It seem reason is same as http://tab.d-thinker.org/showthread.php?tid=2635. I think need to adding a larger swap partition or some physical memory to the VM like zma advice. Actually, we have let watchdog0e0(a vm monitoring server to monitor all VMs ) monitoring mail server. But It not report problem, It seem also watchdog0e0e have some problem.