I'm seeing Iframely embeds missing their numbnails on a bunch of posts lately. Checking my browser console, they're returning 403s with the message "This request does not meet required origin restrictions. iframely.com/docs/allow-origins". Here's some sample posts:
As you can see, the rest of the embed is fine, but the image/thumbnail is missing.
Checking the Iframely docs, I kind of wonder if the key accidentally got restricted to a staging domain instead of prod cohost? https://iframely.com/docs/allow-origins#configure-allowed-origins
I was seeing this problem at the same time Misty and others were. I am not seeing it now and the posts that were previously affected seem to have fixed themselves.