Pointing domain name to folder makes WP disappear

I’ve been building WP sites for over five years, and I’ve never run into this glitch before. I built a site in a subfolder on my main domain (sensibility.com/ofm). The site pulls up fine and dandy if I open it at that URL. Ready to launch the actual site, I pointed its domain at the WP install, but now the site comes up as a list of images and text on a white background–no WP theme formatting whatsoever. Check https://ofmnairobi.org to see what I mean.

What on earth? How can the installation pull up fine in a subfolder but vanish if I point its own domain at it? Did something change in the latest version of WP that causes this to happen?

Thanks for your assistance.

Jennie