Hitting the Collect button for me does nothing, and also hitting the See More button just opens up an empty window. Also, the “Last Day” part is just showing a white box.
Lots of us are having this issue, check out https://forums.505go.com/discussion/38622
Ah, I wasn’t sure if this was the same issue, as I had collected fine right up until today (I missed a couple weekends in January, so I was short of the fatpack anyway). Today was the first day I had trouble collecting the daily reward.