Hyper-V and VM haging up

Hello,

Hyper-v and VM is hanging up when doing backup. I use 3rd party software for backup it works for a 3 months now when backup process starts hyper-v and the VM is hanging up.

I thought windows server backup can me help me, but still same output. I need to restart the server for hyper-v to work again. I hope somebody in microsoft can help me.

Note: Windows server 2012 (Physical and VM)

Thanks a lot.