Backtrace:
          13 (primitive-load
"/gnu/store/fbbpjm8xwq8wbc5pkprim1ilwcb6h9lx-compute-guix-derivation")
In ice-9/eval.scm:
    155:9 12 (_ _)
    159:9 11 (_ #(#(#(#(#(#(#(#(#(#(#(#(#(#(#(#(#<directory (guile-u?> ?)
?) ?) ?) ?) ?) ?) ?) ?) ?) ?) ?) ?) ?) ?) ?))
In ice-9/boot-9.scm:
    152:2 10 (with-fluid* _ _ _)
    152:2  9 (with-fluid* _ _ _)
In ./guix/store.scm:
  2066:24  8 (run-with-store #<store-connection 256.99 7f02dc581be0> _
#:guile-for-build _ #:system _ #:target _)
   1900:8  7 (_ _)
In ./guix/gexp.scm:
   256:18  6 (_ _)
   1137:2  5 (_ _)
   1003:2  4 (_ _)
    849:4  3 (_ _)
In ./guix/store.scm:
  1948:12  2 (_ #<store-connection 256.99 7f02dc581be0>)
   1362:5  1 (map/accumulate-builds #<store-connection 256.99 7f02dc581be0>
_ _)
  1373:15  0 (_ #<store-connection 256.99 7f02dc581be0> _ _)

./guix/store.scm:1373:15: ERROR:
  1. &store-protocol-error:
      message: "some substitutes for the outputs of derivation
`/gnu/store/c8bnwlki4wa6s8rz4ynbcr95imhx3s13-graphviz-2.42.3.drv' failed
(usually happens due to networking issues); try `--fallback' to build
derivation from source "
      status: 1
guix pull: error: You found a bug: the program
'/gnu/store/fbbpjm8xwq8wbc5pkprim1ilwcb6h9lx-compute-guix-derivation'
failed to compute the derivation for Guix (version:
"131265ea3a3d71c3b430bce6bb2d428cc1a2a4fa"; system: "x86_64-linux";
host version: "1.2.0"; pull-version: 1).