On Wed, 2021-03-17 at 19:03 +0000, Charles Jackson via Bug reports for GNU Guix wrote:
> I think the system was broken, and I have since deleted the VM.
>  This is likely not a bug and can probably be dropped.

For what it is worth now the VM has been deleted: the backtrace
is in the HTTP code of the substituter, which has some known
but tricky to identify and fix issues.  The work-around usually
is to run  "guix pull" again.  (Or "guix build", "guix install",
"guix system reconfigure" ...)

So, likely not a broken system, but rather a known issue in guix
that can be worked-around by retrying the command.

In the future, please include the commit of the guix daemon,
as that's were the substitution code is.

Thanks (& closing),
Maxime