There are currently issues with accessing /fs/ess/ locations using ondemand.

Cannot use mpiexec/mpirun from OpenMPI in an interactive session

Resolution: 
Resolved

We found mpiexec/mpirun from OpenMPI can not be used in an interactive session (launched by sinteractive) after upgrading Pitzer and Owens to Slurm 20.11.4. Please use srun only while you use OpenMPI in an interactive session.