When you run Singularity, you’ll want to bind the drive where the data lives to the singularity container. You do that by adding -B /mnt to the singularity command (you can do it right after --cleanenv). Also, you may need to do the same thing with your ~ drive, so singularity can find the license file. Does this make sense?
Thank you very much, Steven. It works great. I think ~ drive ($HOME) is already included in the system defined bind points. See: Bind Paths | Singularity