After taking Defender's advice to change the database prefix and then regenerate the keys, I was unable to login to my super admin account at first. Now I can login, but can't access any of my subsites in the multisite.
Here's an example of subsite that won't load:
Here's the main site that will load:
Any ideas? I was able to do the same recommendations from Defender and Hummingbird on my other WP Multisite without any issues like this. Thanks for your help!