Systematic coredns issue after a few minutes

I have a problem on k3s on which awx was installed.
Everything works perfectly, but after a few minutes (sometimes 10min… other times it reaches 30min) a problem arises with the DNS.
For debugging, I created a pod following these directions (Debugging DNS Resolution | Kubernetes)

$ kubectl exec -ti dnsutils -- nslookup
;; connection timed out; no servers could be reached

If I delete the pod used for debug…

$ kubectl -n kube-system delete pod -l k8s-app=kube-dns
pod "coredns-6799fbcd5-knh54" deleted

… everything starts working again

$ kubectl exec -ti dnsutils -- nslookup
Non-authoritative answer:

but it freezes again after a few minutes.
What could be the problem?

$ kubectl version
Client Version: v1.28.3+k3s2
Kustomize Version: v5.0.4-0.20230601165947-6ce0bf390ce3
Server Version: v1.28.3+k3s2