[Steven Zahm]

@ dominic

You’ve added a custom template file for addresses:
/wp-content/uploads/connections-templates/entry/addresses/address.php

This file is trying to use a function only available to the frontend. You should rename it to address-hcard.php and that should fix it because then the core default address-admin.php should be loaded instead which does not make use of that front end function.

Hope that helps, let me know.