Notification over invoice

Hello,

I'd like to generate a notification when the invoice planned Due Date is near, but I keep getting an error when I try to save it :2021-02-21 16:10:13.803 ***** ERROR ***** [V9.0.4] Exception-[42S22] SQLSTATE[42S22]: Column not found: 1054 Unknown column 'term.initialDueDate' in 'field list'
2021-02-21 16:10:13.804 ***** ERROR ***** [V9.0.4] For query : SELECT term.id AS Term_id,term.initialDueDate AS Term_initialDueDate,term.name AS Term_name,project.name AS Project_name,term.paymentDate AS Term_paymentDate,project.idUser AS Project_idUser FROM term LEFT JOIN project ON project.id=term.idProject WHERE isnull (term.paymentDate)
2021-02-21 16:10:13.804 ***** ERROR ***** [V9.0.4] Strack trace :
2021-02-21 16:10:13.804 ***** ERROR ***** [V9.0.4] #0 Sql->query called at [/var/www/html/projeqtor/model/NotificationDefinition.php:997]
2021-02-21 16:10:13.804 ***** ERROR ***** [V9.0.4] #1 NotificationDefinition->getLines called at [/var/www/html/projeqtor/model/NotificationDefinition.php:1304]
2021-02-21 16:10:13.804 ***** ERROR ***** [V9.0.4] #2 NotificationDefinition->generateNotifications called at [/var/www/html/projeqtor/model/NotificationDefinition.php:441]
2021-02-21 16:10:13.804 ***** ERROR ***** [V9.0.4] #3 NotificationDefinition->save called at [/var/www/html/projeqtor/tool/saveObject.php:110]

And after this, I can't change the screen because it keeps telling me to save or ignore changes which I can't do either save (in error) nor ignore (the button is unavailable).

Can you help me doing this, please?

Thanks a lot.
Regards,
MCanuto

Hello,

here is what I'm trying to do: 
 


When I try to save I get this
 

but I don't know how to create a rule over this element because in the choices I don't have the Client invoice: 


so I'm not able to choose Client invoice's fields to create my message or my rule.

I hope this is more clear now.

Regards,
Mcanuto