I've gone to the help board for this forum and found a dozen or so complaints from all sorts of board admins about the 'Instagram failed to load' error that we have been seeing lately. So far the admins of this forum have not come up with a solution.
There seem to be three theories:
1. Instagram has changed the rules regarding embedding content in pages. I have not seen this happening in other places, so it looks like this is unlikely. 2. Instagram has problems when you try to have too many Instagram posts on one page. Again, unlikely, I have seen it happen with even just one photo. 3. Somehow the board is not handling this correctly all of a sudden. I think this is the most likely answer, but they haven't confirmed.
I'll keep you informed if they come up with an answer or a workaround.