I would request a new key from wunderground.
Make sure you follow the opensprinkler article when requesting.
I remember there was a couple of tricky things when requesting a key.
https://opensprinkler.freshdesk.com/support/solutions/articles/5000017485-getting-a-weather-api-key
I would double check IP address, subnet mask, Gateway and DNS settings on your opensprinkler as well.
I know you can check IP address from the panel. Not sure it comes up with other information.