Kubernetes cluster behind a proxy cant access internet

Cluster information:

Kubernetes version:1.15
Cloud being used: bare-metal
Installation method: kubeadm
Host OS: ubuntu desktop 18
CNI and version: flannel v0.11.0-amd64
CRI and version: docker 18.09.5

I ve setup an on prem kube cluster which doesnt need to be accessed from the outside. The network uses a strict proxy to access the internet. Ive configured docker config json file to use the proxy, everything inside the docker can access internet. Can download and all. The problem is in the kube cluster. The pods can not resolve domain names. So I thought it would be a dns problem.

In my resolv.conf file there are entries for the dns nameserver.

What can I do to troubleshoot this problem ? Can I make coredns use proxy ?