WP Admin on Multisite critical error upon installing

Hi,
We installed according to the docs and experienced a complete lock out of the admin. Had to remove the plugin completely from the back-end to gain access.

Our developer seems to think domain mapping may have something to do with it, and I’m inclined to agree. Is it possible for Duo for WP to conflict with this? Do you have any other tips or suggestions to help us get Duo installed on our WP Multisite?