Import of extra fields not working

With the aid of BP Groups Extras I have created 3 new fields and made these available to all groups. In the groups the fields show under Manage/Extras/All Fields as a dropdown menu. Sofar so goood.
However, the Import button does not function, the fields are not created in the group. What could be the problem?
Regards,
Toon

https://wordpress.org/plugins/buddypress-groups-extras/