How to get on the Duncan Trussell minecraft server?

I’ve been playing minecraft for a while on my laptop, and have successfully managed to sep up a server on it, but, I’m struggling getting onto online servers and really wanted to get onto the www.dtfhmc.com server.

When I go into the multiplayer window in the minecraft ‘UI’ I put the server name in as above, but get the message:

“can’t resolve host name”

Can anybody help?????.......