After installing my pihole, I noticed both Hulu and Netflix updates in my xBox1 queue were listed as Installation Stopped. I disabled the pihole, both installations completed, and I enabled pihole again. Both Hulu and Netflix worked normally. A few days later, I looked at my xBox1 queue again and saw that Hulu, Netflix, and Movies & TV were listed as Installation Stopped again.
Whitelisting dl.delivery.mp.microsoft.com allowed them to complete.
I suspect dl.delivery.mp.microsoft.com was blacklisted because of its involvement with Windows 10 preloading and installation.