bug#45051: Guix pull fails: `In procedure put-string: Wrong type argument in position 1 (expecting open output port): #<closed: string 7f1182257850>`

[pkill9 <pkill9@runbox.com>]

Using guix commit 243512d984e1b870d3b77b2759698a64ed723fea. Also fails
with previous guix revisions.

Full output:

Computing Guix derivation for 'x86_64-linux'... /@ substituter-started
/gnu/store/9ph7spq3b72fv4scqqzwxalb8n0wc6xn-graphviz-2.42.3-doc
substitute -following redirection to
`https://ci.guix.gnu.org/nar/lzip/9ph7spq3b72fv4scqqzwxalb8n0wc6xn-graphviz-2.42.3-doc'...
Backtrace: In ice-9/boot-9.scm: 1736:10  4 (with-exception-handler _ _
#:unwind? _ # _) In unknown file:
           3 (apply-smob/0 #<thunk 7f11836ec3c0>)
In ice-9/boot-9.scm:
    718:2  2 (call-with-prompt _ _ #<procedure default-prompt-handle?>)
In ice-9/eval.scm:
    619:8  1 (_ #(#(#<directory (guile-user) 7f1183311f00>)))
In guix/ui.scm:
  1949:12  0 (run-guix-command _ . _)

guix/ui.scm:1949:12: In procedure run-guix-command:
In procedure put-string: Wrong type argument in position 1 (expecting
open output port): #<closed: string 7f1182257850> @ substituter-failed
/gnu/store/9ph7spq3b72fv4scqqzwxalb8n0wc6xn-graphviz-2.42.3-doc 256
fetching path
`/gnu/store/9ph7spq3b72fv4scqqzwxalb8n0wc6xn-graphviz-2.42.3-doc'
failed with exit code 1 @ substituter-started
/gnu/store/adx3hrrgjs0n55zm4i4p5kv6yj0q3bhq-guile-ssh-0.13.1-debug
substitute killing process 4025 Backtrace: 11 (primitive-load
"/gnu/store/f2ymnsn7d0jv9p8alj4mrg4dpw2fr5vn-compute-guix-derivation")
In ice-9/eval.scm: 155:9 10 (_ _) 159:9  9 (_
#(#(#(#(#(#(#(#(#(#(#(#(#(#<directory (guile-user) 7fc042336f?> ?) ?)
?) ?) ?) ?) ?) ?) ?) ?) ?) ?) ?)) In ./guix/store.scm: 2049:24  8
(run-with-store #<store-connection 256.99 7fc0406ba5f0> _
#:guile-for-build _ #:system _ #:target _) 1883:8  7 (_ _) In
./guix/gexp.scm: 258:18  6 (_ _) 1123:2  5 (_ _)
    982:2  4 (_ _)
    843:4  3 (_ _)
In ./guix/store.scm:
  1931:12  2 (_ #<store-connection 256.99 7fc0406ba5f0>)
   1358:5  1 (map/accumulate-builds #<store-connection 256.99
7fc0406ba5f0> _ _) 1369:15  0 (_ #<store-connection 256.99
7fc0406ba5f0> 7fc0406ba5f0> _ _)

./guix/store.scm:1369:15: ERROR:
  1. &store-protocol-error:
      message: "some substitutes for the outputs of derivation
`/gnu/store/d879bxb47cnzkgsl37478aa4mmp7cjdg-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/f2ymnsn7d0jv9p8alj4mrg4dpw2fr5vn-compute-guix-derivation'
failed to compute the derivation for Guix (version:
"4cf3734c56d669ee2d78082e5d7c4d0a58e0f800"; system: "x86_64-linux";
host version: "243512d984e1b870d3b77b2759698a64ed723fea"; pull-version:
1). Please report it by email to <bug-guix@gnu.org>.