[WPMU DEV DASHBOARD] cannot access WPMUDev dashboard on the network site at all

I have a Multisite - running Avada theme, and cannot access WPMUDev dashboard on the network site at all. Funny thing is, if I copy the complete Multisite to a staging platform (Duplicator Pro) the WPMUDev dashboard is accessible on staging.
Is there anything I can do on my production site (without shutting down all plugins), such as a reinstall plugin or a DB parameter I can reset to get WPMUDev accessible?? I've got a couple WPMU plugins to update.
Regards,
Scott