I'm not sure why it's throwing a Nonetype error, that's probably a bug. But the actual error seems pretty clear--you've got an invalid server.version value in your vizalerts.yaml. Set it to 10 and this should be fixed.
Still got an error after edit the vizalerts.yaml. Here is the error :
HTTPError generating trusted ticket: Proxy Authentication
Is that the full error? Are you using a proxy? Does it require authentication? You may need to work with your networking team on this one.