Unexpected behaviour when substitutes is down

[Simon Tournier]

Hi,

Today (Sunday May, 21th), apparently ci.guix.gnu.org (Berlin) is down.
Well, that happens, sadly!  However, it appears to me unexpected that
any action requiring substitutes is just impractical.  In plain words,
Guix is unusable for me.

Using Guix 14c0380 pulled on May 19th, for instance

    guix shell hledger

loops forever; or almost.  Similarly when using “guix time-machine” or
any else requiring substitutes.  I thought these kind of troubles had
been fixed; last time similar troubles appeared.  Other said, I was
expecting to either fallback or raise an error (ideally reporting a
meaningful message).

Well, before opening issues on that topic, maybe people have already
clues about what could be fixed and where.  Any ideas?

Cheers,
simon