I was having a problem yesterday with storage. My best bad idea was to resize the template storage from 20 GB to 200 GB. Now my main app VM, based on that template, just won’t start.
Error says: "Cannot connect to qrexec.agent for 60 seconds, see /var/log/xen/console/guest-Fatima.log for details.
Which says: "Job qubes-rootfs–resize.service/start running (57s / no limit).
The app VM closes itself.
Well, I fixed it by moving the 2 important app VMs to a similar template I had.
This could be a community guide too 
have a backup for your important templates, in case you break something.
did you started the template ater the resize?
In this sort of case you can always extend the timeout period, using
qvm-prefs QUBE qrexec_timeout SOME_VALUE in dom0.
Once the initial check has completed and the template has started, you
can return the value to a sensible value.
I never presume to speak for the Qubes team.
When I comment in the Forum I speak for myself.
You are probably right @Zrubi I don’t remember anymore (it was yesterday) but probably I did not started the template, which now sounds like a foolish omission of mine. Next time I will do an ordered process.
I did not know about the possibility of extending the timeout period @unman thank you very much for letting me know.