Hi Guix, I can reproduce this rather easily on my system:
--8<---------------cut here---------------start------------->8--- $ ./pre-inst-env guix build icedove The following derivations will be built: /gnu/store/l6r93asndd0kwv7024iyrl71zd0lbpbq-icedove-102.7.2.drv /gnu/store/8zi808086b3vlfjrhdm87fgljziwdqx2-icedove-l10n-102.7.2.drv /gnu/store/v0sq7rb8fk36kjasb27a71z1a27wxb1s-icedove-minimal-102.7.2.drv process 19542 acquired build slot '/var/guix/offload/localhost:6666/0' normalized load on machine 'localhost' is 0.08 building /gnu/store/8zi808086b3vlfjrhdm87fgljziwdqx2-icedove-l10n-102.7.2.drv... process 19548 acquired build slot '/var/guix/offload/localhost:6666/1' normalized load on machine 'localhost' is 0.08 building /gnu/store/v0sq7rb8fk36kjasb27a71z1a27wxb1s-icedove-minimal-102.7.2.drv... guix offload: sending 1 store item (558 MiB) to 'localhost'... exporting path `/gnu/store/bwb5hcdyzgq16kmbsva7ax0zq6lzg78z-icedove-102.7.2.tar.xz' guix offload: error: failed to connect to 'localhost': Timeout connecting to localhost cannot build derivation `/gnu/store/l6r93asndd0kwv7024iyrl71zd0lbpbq-icedove-102.7.2.drv': 1 dependencies couldn't be built guix build: error: build of `/gnu/store/l6r93asndd0kwv7024iyrl71zd0lbpbq-icedove-102.7.2.drv' failed --8<---------------cut here---------------end--------------->8--- The third derivation tries to get a build slot and times out, because the first two have already saturated the bandwidth of the link and it takes more time than expected to get a reply. The workaround is to use '-k', for "--keep-continuing", and retry the 3rd failing derivation after the first two completed. I don't have a clear idea on how to improve the situation other than use longer timeouts... but perhaps these timeouts could be dynamic based on the load of the network/CPU/ ? -- Thanks, Maxim