When I first installed the action user addon I was able to assign users to events. That no longer works and trying to do so results in a loading graphic until cancelled. Users are still able to log in and create events but I cannot apply them to events I have created on their behalf.
Jan 15,2017 AT 10:30AM - 5 years ago -Hi,
Please disable all other plugins then change the theme to default WP theme temporarily and check once.