Trouble adding a repository (retrieving gpg key timed out)

I’m trying to install the Elmer csc software, and I pasted the command line exactly as it is from their site:

sudo apt-add-repository ppa:elmer-csc-ubuntu/elmer-csc-ppa

I get the following:

Archive for the monolithic Elmer FEM software ubuntu packages.

More info: https://launchpad.net/~elmer-csc-ubuntu/+archive/ubuntu/elmer-csc-ppa

Press [ENTER] to continue or Ctrl-c to cancel adding it.

Error: retrieving gpg key timed out.

^C

I pressed Enter every time.

Can somebody hep me please?