I assume you cannot get points for rooms you book through United Mileage Plus, but I would like to add them to my Hhonors account so they show up on my list of reservations. Is this possible?

I have confirmation numbers for two stays I booked using Miles and Money through the UA website, but when I go to try and add them to my reservations on the HHonors page I get "please enter a valid confirmation number"

Any suggestions?