Hello -

I've tried to put this apex trigger in our sandbox: https://help.salesforce.com/articleView?id=entitlements_auto_add.htm&type=5
The purpose is to automatically add Entitlements to Cases from Web, Email, and Communities. 
I follow all the steps given in that article. But when I submit the trigger, I receive several errors, starting with "Compile Error: Variable does not exist: contactIds".

Do you know how to make this trigger work ?

Thank you!