Comment 20 for bug 1725062

heytimc, i blocked pptp connection on my router and got the same syslog errors.
So your problem is some kind of network issue. It could be your router firewall, or ISP firewall or maybe your IT department changed something or blocking it. I can only quess.
As a confirmation of my words - open gnome-terminal, type nmtui, choose connect and select your VPN connect - if will fail too, so it means it's a network issue.