Fatal error when opening website/dashboard

Hi there,

fatal error message appears when trying to access the website with membership 2 pro plugin installed.

the message is:
Fatal error: Class MS_Addon_Automessage contains 1 abstract method and must therefore be declared abstract or implement the remaining methods (MS_Addon::get_id) in /home/clisrcom/public_html/wp-content/plugins/protected-content/app/addon/automessage/class-ms-addon-automessage.php on line 24

website address:
http://imageft.clisr.com/

i've just granted the access.

thanks,
Bart