Login Loop Happening for All Users

It seems that some sort of login loop has been created in my Wordpress environment. I've tried everything, but can't figure out what's causing it. The only way I can get in is to rename the plugins folder and/or disable all plugins. It seems the one causing the issue is "Domain Mapping". However, I just did a network uninstall on that plugin and removed the "Sunrise" items it had me do on the wp-config and sunrise.php file and I can no longer login under any situation (plugins or not).

Might anybody be able to lend a hand and/or point me in the right direction?