Why won't my Instagram let me like photos?

I'm trying to like my ex's photo. I have the iPhone 4 iOS 6 but got the new ig update… The ex hasn't blocked me but hasn't talked to me since I put up a wcw as my Bestfriend who is a girl obvi. So I guess she is mad but I'm still following her and she is following me… I can't like her recent photo and I deleted my ig all downloaded it and signed in and the same thing… Why is it doing this to me?

Sorry I'm not sure, I don't have instagram.

Maybe she has some sort of privacy setting where you can't like it? That's all i can think of if you deleted and redownloaded and everything.