Redirect loop on one blog of multisite install after plugin upgrade

I upgraded my plugins today (I can’t remember which four plugins exactly but I know one was Jetpack and one was WordPress Importer) and suddenly I get an error:
“This webpage has a redirect loop
The webpage at https://www.davidjmiller.org/wp-admin/users.php?page=s2_users has resulted in too many redirects.”

I have found that every page I try to visit at that site (www.davidjmiller.org) gives me the error but all my other subdomains are working fine (ex. plugins.davidjmiller.org)

Any ideas on how to fix this?