As of Fri Nov 12 03:23:10 PM EST 2021 the s390x builder appears to be missing in action -- can't see any recent builds (24 hours) on https://farmer.golang.org/ for it, and I am unable to create a gomote.
Sorry for the late reply, and thanks @jonathan-albrecht-ibm for looking into it. I am on vacation till November 17. If this issue still exists, let me or Jon know, I will help look more into it when I am back. Thanks.