Here's another instance: https://ci.guix.gnu.org/eval/528710
More information:
Log:
Greetings,substitute: substitute: [Kupdating substitutes from 'http://141.80.167.131'... 0.0%guix substitute: warning: 141.80.167.131: connection failed: Connection refused substitute: cannot build missing derivation ?/gnu/store/4gqj2byvj9zz30wzvwkbijpya3vn1bjw-rust-dogged-0.2.0.drv?