You can change the contact list, or a contact list and filter template association in a campaign only if the campaign is in a running or callback state.
You can associate a filter template to a contact list, only if the attributes in the filter template are present in the contact list.
For an attribute-based campaign, ensure that the filter template you associate to the contact list of the campaign does not contain sort condition attributes that are already configured as attributes for attribute-based dialing in the Campaign Creation Wizard of the campaign in POM. This is because POM, by default, sorts the filtered contacts based on the attribute-based dialing attributes.
If the Contact Record Assignment to Agent option is set as Attribute or Agent ID or both for an attribute-based campaign in POM, ensure that the contact list you add contains the attributes that are selected for the attribute/agent ID-based record assignment.