bug#65560: You found a bug:

[Simon Tournier]

Hi,

Thanks for your report.

On Sun, 27 Aug 2023 at 08:25, Rua via Bug reports for GNU Guix 
<bug-guix@gnu.org> wrote:
> guix pull

[...]

> 1. &store-protocol-error:
> message: "some substitutes for the outputs of derivation 
> `/gnu/store/gm8pw2qwi35d5nc5dz7gqagp0yjmjlp2-po4a-0.69.drv' failed (usually 
> happens due to networking issues); try `--fallback' to build derivation from 
> source "

Oups, so bad user experience and unfriendly message.  Sorry.

Have you tried

    guix pull --fallback

?

Cheers,
simon