E-newsletter not working

The e-newsletter plugin functionalities do not work anymore at our site haganum.nl after upgrading to the latest wordpress and plugin versions. We experience these issues:

- Sending newsletter: pushing Send newsletter now button opens 'Sending' page and shows message: The Newsletter was sent to 0 out of 1 members and stops loading. Newsletter was not sent.

- Buttons do not react in members screen: clicking edit button to edit a member: no reaction (console: Uncaught TypeError: jQuery(...).editMember is not a function at HTMLInputElement.onclick (admin.php?page=newsletters-members:959) onclick @ admin.php?page=newsletters-members:959.) Same for 'Change groups' button (console: ncaught TypeError: jQuery(...).changeGroups is not a function at HTMLInputElement.onclick (admin.php?page=newsletters-members:957) and Delete button (ncaught TypeError: jQuery(...).

- buttons stopped working: all other buttons do not work in edit member groups

- settings page is empty: only Save newsletter settings buttons is visible: rest of screen is emtpy.

Hopefully you will be able to reproduce and solve these issues?

Kind regards,