VPN client no longer connecting
I had the same exact error log, but with having admin access to vpn server and router, so I found out the problem quickly. For me it was dst-nat problem, on one  router that I forgot about being there and I found it via traceroute. I was playing with it and some testing vpn-servers 2 years ago.

So basically this log would show up if no packets on 500/udp or 4500/udp are able to reach the server or just end up redirected to non-existing address(like my case). There's most likely no problem with your colleague's mac. The log would just say something else if there was something like bad configurations, secret, cipher, outdated operating system etc. I recommend to contact your office if you haven't yet and tell them your IP.