AppVM private storage is borked

I have an AppVM named “chess”. It is out of space for some chess app I am developing. I tried to increase the private storage size from 20 GB to 30 GB via the Qubes Manager, and received some error message on dom0 that I do not recall. The Qubes Manager still reported the private storage size as 30 GB (maybe a UI bug?). From my chess AppVM, I still was lacking disk space. Then I restarted by laptop, hoping that would solve it. The space is still 20 GB. I tried increasing again from 30 GB to 40 GB in Qubes Manager - this time no error message, but the space still appears 20 GB. I’ve tried looking for relevant logs in journalctl to retrieve the old error message I dismissed, but haven’t been able to find it.

Any advice on how to resolve this? It seems my AppVM filesystem is borked.