Hello, I try this command below with root access and it doesn't seem to 
work:

# https_proxy=http://xxxx:yyyy/ http_proxy=http://xxxx:yyyy/ guix pull
Mise à jour du canal « guix » depuis le dépôt Git « 
https://git.savannah.gnu.org/git/guix.git »...
Authentification du canal « guix », commits 9edb3f6 à 6a77596 (92 
nouveaux commits)...
Construction depuis ce canal :
   guix      https://git.savannah.gnu.org/git/guix.git    6a77596
substitute: guix substitute: warning: ci.guix.gnu.org : la connexion à 
échouée : Connexion refusée
substitute:
substitute:
construction de 
/gnu/store/5a5s2j7bqjdg73j4w94v2jw85qf6ghqc-module-import.drv...
construction de 
/gnu/store/5gh5ynrk98yssq05ggpc20iml7b436sj-module-import-compiled.drv...
construction de 
/gnu/store/9fk4ixnqnkcd4nn808mcgdp86nv6yry4-compute-guix-derivation.drv...
Computing Guix derivation for 'x86_64-linux'... \substitute:
substitute:
substitute:
substitute:
substitute:
@ substituter-started /gnu/store/mzfkrxd4w8vqrmyrx169wj8wyw7r8i37-bash 
substitute
substitute:
guix substitute: error: connect: Connexion refus?e
@ substituter-failed /gnu/store/mzfkrxd4w8vqrmyrx169wj8wyw7r8i37-bash  
fetching path `/gnu/store/mzfkrxd4w8vqrmyrx169wj8wyw7r8i37-bash' (empty 
status: '')
Backtrace:
           13 (primitive-load 
"/gnu/store/vkgqimg8fz7zi1dyv4j7jmlj4ml1gsqr-compute-guix-derivation")
In ice-9/eval.scm:
     155:9 12 (_ _)
     159:9 11 (_ #(#(#(#(#(#(#(#(#(#(#(#(#(#<directory (guile-user) 
7f82e816ff?> ?) ?) ?) ?) ?) ?) ?) ?) ?) ?) ?) ?) ?))
In ./guix/store.scm:
   2062:24 10 (run-with-store #<store-connection 256.99 7f82e65045f0> _ 
#:guile-for-build _ #:system _ #:target _)
    1896:8  9 (_ _)
In ./guix/gexp.scm:
    258:18  8 (_ _)
    1123:2  7 (_ _)
     982:2  6 (_ _)
     843:4  5 (_ _)
In ./guix/store.scm:
   1944:12  4 (_ #<store-connection 256.99 7f82e65045f0>)
    1362:5  3 (map/accumulate-builds #<store-connection 256.99 
7f82e65045f0> _ _)
   1373:15  2 (_ #<store-connection 256.99 7f82e65045f0> _ _)
    719:11  1 (process-stderr #<store-connection 256.99 7f82e65045f0> _)
In ./guix/serialization.scm:
      80:6  0 (read-int #<input-output: file 10>)

./guix/serialization.scm:80:6: In procedure read-int:
ERROR:
   1. &nar-error:
       file: #f
       port: #<input-output: file 10>
guix pull: error: You found a bug: the program 
'/gnu/store/vkgqimg8fz7zi1dyv4j7jmlj4ml1gsqr-compute-guix-derivation'
failed to compute the derivation for Guix (version: 
"6a77596cab2c173b04efff0a271a8e3972ca7499"; system: "x86_64-linux";
host version: "dbf4561b00263d6c0cf7f294e1a6a8bebf382b46"; pull-version: 1).
Please report it by email to <bug-guix@gnu.org>.