I noticed that Guix cannot download any tarballs from github.com. For example:
------ $ guix build -S python-sphinx-gallery --no-substitutes The following derivation will be built: /gnu/store/qrlcbnin47j1i4slyc9j8hvpczp1l9n8-python-sphinx-gallery-0.1.13.tar.gz.drv building /gnu/store/qrlcbnin47j1i4slyc9j8hvpczp1l9n8-python-sphinx-gallery-0.1.13.tar.gz.drv... Starting download of /gnu/store/ks605lq7q0zf1agf84mslbk2cgdkg5hy-python-sphinx-gallery-0.1.13.tar.gz >From https://github.com/sphinx-gallery/sphinx-gallery/archive/v0.1.13.tar.gz... Throw to key `gnutls-error' with args `(#<gnutls-error-enum Resource temporarily unavailable, try again.> read_from_session_record_port)'. [...] ------ The server is advertising TLS 1.3 support. Marius suggested that the Guix snapshot needs to be updated to include commit e4ee84202633636b4c8cef4a332f0c74912a3b23 (download: Ask not to use TLS 1.3.), and I am testing this now.