Error: failed to synchronize cache for repo ..." when using Fedora-26 as sys-net

[joev...@gmail.com]

Qubes OS version R4.0 (RC4)
fedora-26

After installing fedora-26 template new, and updating to latest build. I configured sys-net to use this template.

dnf clean all
qubes.InstallUpdatesGUI or sudo dnf update

When using fedora-26 as the sys-net template... it seems to block the ability to perform updates. I get "Error: failed to synchronize cache for repo" whenever I try after clearing cache.

Anyone else experiencing this? Is fedora-26 fully capable?

[joev...@gmail.com]

https://github.com/QubesOS/qubes-issues/issues/3557

Related to:
https://github.com/QubesOS/qubes-issues/issues/3135

Root cause:
When changing TO fedora-26, the qubes-updates-proxy service fails to start on boot. A manual start of the service fixes the issue. A reboot seems needed to have it start on boot. Not a problem since sys-net changing templates is rare. I just didn't assume a reboot or manual service start would be needed.
No problem going FROM fedora-26 to another template, as the service starts properly on first run.

Solution:
running 'systemctl restart qubes-updates-proxy' in sys-net