Proxmox Nat Networking Issue
Solution 1:
I found my mistake when i was sleeping, so i woke up immediately and fixed this. The interface which is doing nat networking is vmbr1 but when i setup virtual machine i was assigning wrong bridge mode (vmbr0) to network device.
To fix this i stopped virtual machine and edited bridge mode from vmbr0 to vmbr1. Now everything works fine.