Hm... this is strange. I'll investigate this.

The cover image the api provides is https://cdn.pixabay.com/photo/2015/09/17/10/31/banner-943868_960_720.jpg
It opens correctly in my browser. Maybe it has something to do with pixabay. But I don't know yet.

A workaround would be to adjust the html manually in the 'template option. Same with the avatar. If you would like to use it anyway, I'd love to help you with that.