Friend invites weren't sent

Hello,

I sent 3 invites to some friends of mine. One is reporting he got in, and another is saying he never got an email or survey on the playtesting website. Is there an issue w/friend invites or a delay? Any help would be so appreciated, he hasn't been accepted and he's been trying to get in from the beginning. He's pretty down about it haha.

Thanks in advance!