If you try to access https://launchermeta.mojang.com/mc/game/version_manifest.json or https://piston-data.mojang.com/v1/objects/145ff0858209bcfc164859ba735d4199aafa1eea/server.jar the connection can be intermittent. I captured this on a network test using Cisco ThousandEyes. In the path trace you can see that my New York agent is unable to reach the target, while the Atlanta agent has no issue. It appears to be a regional issue. 

I had issues with this same thing yesterday and it self-resolved after a while. Now today the issue has re-occurred again.