Again, I am not hampered by any knowledge on the topic, and am just echoing a very general thing. You stated that you attempted to install UPS support without nethserver-collectd and collectd-nut. Then you added them. Theoretically that could mean that these later two options should be present when installing the first. Again, without being hampered by any knowledge on the topic.
If uninstalling all, and reinstalling with either these options immediately selected OR installed first, doesnt help, then I am not going to be of help I’m affraid.
The manual doesnt state much, you’d think it would just work
I do know that the servermanager is not always useful with errors. It creates errors by default when I create users, but did everything it had to do anyway … sometimes just repeating the exact same thing that caused the error, will pass the second time.
As I am unsure yet if this is my own fault or NethServer implementation specific, I just ignore them for now. A good example of this is installing the AD account provider, which always fails the first time for me, then I press OK again, and it works. Perhaps due to doing everything from first boot (install, add, etc.) or because I do not want to use the proposed AD.DOMAIN.TLD but just DOMAIN.TLD.
Sorry I can not be of more help.