Error: Can't create new employee

Hi JoomDonation-Team,
I just purchased the Services Booking Extension and went thru the setup. But when I try to save a new employee it ends.

An error has occurred.

    0 Field 'client_id' doesn't have a default value

Call Stack
#     Function     Location
1     ()     JROOT/administrator/components/com_osservicesbooking/classes/employee.php:754
2     OSappscheduleEmployee::employee_save()     JROOT/administrator/components/com_osservicesbooking/classes/employee.php:63
3     OSappscheduleEmployee::display()     JROOT/administrator/components/com_osservicesbooking/osservicesbooking.php:156
4     require_once()     JROOT/libraries/src/Dispatcher/LegacyComponentDispatcher.php:71
5     Joomla\CMS\Dispatcher\LegacyComponentDispatcher::Joomla\CMS\Dispatcher\{closure}()     JROOT/libraries/src/Dispatcher/LegacyComponentDispatcher.php:73
6     Joomla\CMS\Dispatcher\LegacyComponentDispatcher->dispatch()     JROOT/libraries/src/Component/ComponentHelper.php:361
7     Joomla\CMS\Component\ComponentHelper::renderComponent()     JROOT/libraries/src/Application/AdministratorApplication.php:150
8     Joomla\CMS\Application\AdministratorApplication->dispatch()     JROOT/libraries/src/Application/AdministratorApplication.php:195
9     Joomla\CMS\Application\AdministratorApplication->doExecute()     JROOT/libraries/src/Application/CMSApplication.php:306
10     Joomla\CMS\Application\CMSApplication->execute()     JROOT/administrator/includes/app.php:58
11     require_once()     JROOT/administrator/index.php:32

Could you please help me out?
Thanks!

Hi Omo Kobsen,
I have just answered you through our Ticket system
Thanks
Dam