Never Loading with Smugmug Gallery

I’ve set up Supersized and integrated a Smugmug gallery into this article https://www.ispithotfire.com/2012/01/22/call-it-redemption-the-49ers-move-on-and-i-was-there-to-witness-it/.

However, I only see a loading icon. I don’t believe anything will ever load, and I am not clear what the problem could be. I don’t have any other image plugins and I also tried resetting the settings to no avail.
This is the gallery on Smugmug: https://ispithotfire.smugmug.com/2012/49ers-vs-Saints-The-Grab

Can anyone suggest tips I can try? Thanks in advance for your time!

https://www.ads-software.com/plugins/wp-supersized/