Unable to give reputation to user

[louisstephens]

I guess this is the right place to post this. Just this morning I went to like an answer someone had given, and was met with a popup stating: "Unable to give reputation to this user". Has anyone encountered this before, or is there some "cap" on users with a certain ratio (reputation to posts) that is keeping me from providing reputation. It was not a big deal, but I wanted to give credit to where credit was due.

[diogo]

Hi Louis, I suspect that this might have to do with the user himself. Can you indicate the user and post in question? 

[louisstephens]

It was DaveP and the post was 

At first I couldn't "like" the post, and I received the message in regards to reputation. After a while, I was able to hit "like".