When I try to export a PDF in the GUI, I get the following error message:

error { target: img, isTrusted: true, srcElement: img, currentTarget: img, eventPhase: 2, bubbles: false, cancelable: false, returnValue: true, defaultPrevented: false, composed: false, … }

I am using the Apache Superset 4.1.1-dev image.

Celery and Redis are running.

Can anyone help me?