Hi, we have an issue with the latest versions of the Kubernetes Plugin and Kubernetes clusters that need to connect via proxy. These are the steps how to reproduce it

1. Make sure in the controller there is one of latest version of the Kubernetes plugin. I.e. 3842.v7ff395ed0cf3
2. Configure a proxy in the controller and add in the "No Proxy Host" field some hostname with wildcard, i.e. *.myhost.com
3. Add a new cloud configuration and mark the "Use Jenkins Proxy" checkbox
4. Click on test connection button.

You will get an error message like this

Error testing connection https://xxxxxxx: java.net.MalformedURLException: NO_PROXY URL contains invalid entry: '*.myhost.com'

If you try to run a job using that cloud configuration you will get the same error.