Hi Ludo,
Hi Guix,

while trying to build a new installer-image, I encountered:

 nss-certs-3.44.1  150KiB                                                                                  4.0MiB/s 00:00 [##################] 100.0%

sha256 hash mismatch for /gnu/store/32hy1jqkam201l7c4wg3bhxz4x5l5jy0-nss-certs-3.44.1:
  expected hash: 0vbkb5mcwzbz4lm1c1319pail61785sd3lj6526vl5hdnp1rxyad
  actual hash:   1awgljvsvc141350xyjjnb15hk66qpcpzwz0hrly11yfbw6wn7cv
substitution of /gnu/store/32hy1jqkam201l7c4wg3bhxz4x5l5jy0-nss-certs-3.44.1 failed
killing process 29347
guix system: error: some substitutes for the outputs of derivation `/gnu/store/br6w1qmw2b98c6fa45gy0ljqdzjw70vr-nss-certs-3.44.1.drv' failed (usually happens due to networking issues); try `--fallback' to build derivation from source 


I'm seeing this around for a while now. Sometimes it works, sometimes
not.

Any ideas on how to fix this?

Is this related to the closed:

https://debbugs.gnu.org/cgi/bugreport.cgi?bug=33603

Is this related to the docker-bug we had lately:

https://debbugs.gnu.org/cgi/bugreport.cgi?bug=36215

Also, there was one sha256-mismatch for ruby-sass:

https://debbugs.gnu.org/cgi/bugreport.cgi?bug=35437

Is this a package-specific problem or a general configuration problem
on Berlin (or one of its slaves)?

Björn