I see, I hope that really solves your problem cause so far on my side I was able to try a separate qube for updating Templates and dom0 So far so good there were no problems given the fact that I ensured that the qube responsible for being updates proxy to the Templates were resolving DNS queries just fine and updates proxy service actively running properly in that qube.
If you still got the problem after switching to debian-10 maybe do some network diagnosis in your update vm? I can lend a helping hand with that if you need it -- You received this message because you are subscribed to the Google Groups "qubes-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to qubes-users+unsubscr...@googlegroups.com. To post to this group, send email to qubes-users@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/qubes-users/ed09218f-0794-4dc0-a28d-6907854de4b7%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.