My password doesn't work but i know it is the correct one.
I am getting a "connection refused" error messsage when trying to connect to the cluster
The cluster is only accessible from on campus or via VPN and you are likely not on either. If you already have vpn access, you can connect to that first and then to the cluster. If you have a machine on campus you can connect to remotely, you can connect there and then into the cluster.
I requested a lot of cores on a computer, but it is only using one.
If it is not an MPI job, then you executable may not be multithreaded, or you didn't specify the number of threads. If you know your application is multithreaded using openMP but it isn't using the additional cores, you may need to set the appropriate environment variable. Often you need to set something like the following:
Nested SRUNS fail on GPU nodes.
If you experience srun calls hanging on GPU nodes after starting an interactive session add this variable to your environment.