Be sure the sales and marketing users who plan to use Customizable Campaign Influence have the Sales User permission set assigned with the Campaign Influence permission enabled.
|Available in: Salesforce Classic and Lightning Experience|
|Available in: Professional, Enterprise, Performance, and Unlimited Editions|
|To assign permission sets:||“Customize Application”|
This information applies only to Customizable Campaign Influence and not to the original version of Campaign Influence.
Add the Sales User permission set to user profiles assigned to users who plan to track campaigns that influence opportunities.
In the Sales User permission set, enable the Campaign Influence permission.