For me it is working fine now. These are the steps that I followed in ubuntu 20.04 LTS.
Thanks for the information. Unfortunately I haven't been able to get FRAME work interactively on my macOS machine. I've restarted the machine, update and upgraded conda, and re-insalled PyFerret . Nothing seems to change.
As far as I can tell, only the "-nodisplay" mode gives a correct PNG file.
Ryo