The host is to blame for the error. If I'm not mistaking, its a DNS issue. MyVMK.com is hosted by cloudflare, so I don't really have any experience with them. Other hosts, such as 1and1 have this issue, and honestly the only way to fix it with them was to contact customer support.
This website proves that its just you having the issue:
http://www.downforeveryoneorjustme.com/myvmk.com
I've been able to resolve this in the past (on the client side, not the server side) by going into my router and connecting to google's dns:
https://developers.google.com/speed/public-dns/
Currently, I'm at college, so I have no access to the router. Feel free to try it on your own though.