New installation - no connection to plugins server

I want to learn Jenkins so I installed it on my Kubernetes setup (Minikube locally) using the jenkins/jenkins:lts image. But when I log in to Jenkins is has the problem of not being able to connect to the plugins server. I have used many hours going through Stackowerflow etc to find a solution, like changing the url from https://updates.jenkins.io/update-center.json to just using http.
I’m not behind a corporate firewall, it’s just on a local machine connected to an ordinary router. Do I really need to set up a proxy server or is there another fix?