snap not working on buster

I followed the instructions at https://riseup.net/en/vpn/betatest/linux to install the snap package on my buster system

# snap list
Name        Version    Rev   Tracking  Publisher   Notes
core        16-2.37.4  6531  stable    canonical✓  core
riseup-vpn  0.19.2     126   stable    leapsnaps   classic

It setup a menu entry (with a broken icon) and when I select it I get an error. See attached screenshot.