R8000P DHCP issue

The systems connected to router cannot connect to intenet using DHCP from router but works fine after assigning manual IP.

Unchecked the option of Use Router as DHCP Server and rebooted. Again checked the same and rebooted but issue remains the same. 

We are using ACT Fibernet. Checked with them and there is no issue from their end.

System used to connect with internet without manual IP assignment.