Could be many things, although fundamentally it's simple: the computer running ATK can't connect to the license server.
I think the first part of this warning can be ignored, but generally you need to start troubleshooting by trying simple things. Which machine is the error message from? Can ATK run on this machine when you just execute "atkpython"?
If this is part of a cluster setup, you should check basic things like if login files (.bashrc) are sourced for MPI jobs. If not, you can place the environment variables for the license system in the submission script.
