Thank you for your answer,

it seem's proxy failure (are only 80 and 443 ports used for pull?). When 
I am outside (i.e. without proxy), it's working well...

The new command gives the same error:

# https_proxy=http://xxxx:yyyy/ http_proxy=http://xxxx:yyyy/ guix 
time-machine --commit=dbf4561b00263d6c0cf7f294e1a6a8bebf382b46 -- 
time-machine --commit=6a77596cab2c173b04efff0a271a8e3972ca7499 -- help
Mise à jour du canal « guix » depuis le dépôt Git « 
https://git.savannah.gnu.org/git/guix.git »...
Mise à jour du canal « guix » depuis le dépôt Git « 
https://git.savannah.gnu.org/git/guix.git »...
Computing Guix derivation for 'x86_64-linux'... /substitute: guix 
substitute: warning: ci.guix.gnu.org : la connexion ? ?chou?e : 
Connexion refus?e
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) 
7f98428d0f?> ?) ?) ?) ?) ?) ?) ?) ?) ?) ?) ?) ?) ?))
In ./guix/store.scm:
   2062:24 10 (run-with-store #<store-connection 256.99 7f9840c645f0> _ 
#: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 7f9840c645f0>)
    1362:5  3 (map/accumulate-builds #<store-connection 256.99 
7f9840c645f0> _ _)
   1373:15  2 (_ #<store-connection 256.99 7f9840c645f0> _ _)
    719:11  1 (process-stderr #<store-connection 256.99 7f9840c645f0> _)
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 time-machine: 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>.

All the best,

Laurent

-- 
Laurent Cournède
Institut des Matériaux Jean Rouxel (IMN)
https://www.cnrs-imn.fr
2 rue de la Houssinière
BP 32229 - 44322 NANTES CEDEX 3
Tél : 02.40.37.39.06

Le 29/01/2021 à 16:26, zimoun a écrit :
> Hi,
>
> On Fri, 29 Jan 2021 at 15:52, Laurent Cournède
> <Laurent.Cournede@cnrs-imn.fr> wrote:
>
>> # 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
> Hum, maybe it is transient network failure.
>
>> substitute:
>> guix substitute: error: connect: Connexion refus?e
>> @ substituter-failed /gnu/store/mzfkrxd4w8vqrmyrx169wj8wyw7r8i37-bash
>> fetching path `/gnu/store/mzfkrxd4w8vqrmyrx169wj8wyw7r8i37-bash' (empty
>> status: '')
>> Backtrace:
> Thanks for the report.  It should not fail this way.
>
>
>> failed to compute the derivation for Guix (version:
>> "6a77596cab2c173b04efff0a271a8e3972ca7499"; system: "x86_64-linux";
>> host version: "dbf4561b00263d6c0cf7f294e1a6a8bebf382b46"; pull-version: 1).
> Mimicking pulling from dbf4561b00263d6c0cf7f294e1a6a8bebf382b46 to
> 6a77596cab2c173b04efff0a271a8e3972ca7499 with:
>
> --8<---------------cut here---------------start------------->8---
> guix time-machine --commit=dbf4561b00263d6c0cf7f294e1a6a8bebf382b46 \
>    -- time-machine --commit=6a77596cab2c173b04efff0a271a8e3972ca7499 \
>    -- help
> --8<---------------cut here---------------end--------------->8---
>
> works here.  What does it do on your machine?
>
> Noting that you pulled something between because of "Authentification
> du canal « guix », commits 9edb3f6 à 6a77596".
>
>
> All the best,
> simon
>