I've been getting calls from this number too. I'm not sure how Donor Services is based in Minnesota as 661 is a California area code. I did pick up once and heard the robocall message. I'll be calling Verizon, my provider, to block the number (it's free with Verizon to block numbers).
I have been receiving daily calls for a few weeks now. I have answered twice, and don't stay on the line long enough to hear anything. I highly doubt these calls have anything to do with HRC. I am not a contibutor, and I am receiving this calls. I figure the claims I read from someone else's post about being related to "a nonprofit you support" are also bogus.