I can no longer book a registration in backend

Since a few weeks I am no longer able to book a registration in backend.
I only allow registration for registered users. Sometimes I will book the registration myself in the backend.
When I click the 'select user' link I get the popup with the list of registred users. But when I click on a user name, nothing happens. The popup stays on the screen. It does not return to the 'New registration' screen with the selected user.

it worked fine until some weeks ago. I did not change any settings.

Hi Erik

You did make the change (update to Joomla 3.5.x )

Joomla 3.5.0 made some change to the API, so you will need to update your site to latest version of Events Booking (2.7.0). After that, it will work well

Regards,

Tuan