VM Client Backup in Hung state in VADP Config with VIP Netbackup

Friends,

I am facing weird situation here & need your help..

I have Vm policy configured with VADP & VIP (Vmware inteliggent policy query).

My VM policy has 100+ Vm client backing up with VADP & out of which Only one VM client is going in hung state from last 1 week.Prior to that it was running fine.

My master is on Linux,backup host is windows 2k8,NBU version is 7.6.1.2.

i did google but couldnt find usefull information to fix slow or hung Vm backup in VADP configuration.

Please help me to troubleshoot the root cause..