The suppression list feature of the campaign process allows multi-selection of suppression files. To apply your suppression list, follow the steps below to ensure the list is being applied to the campaign.
1. In step 3 of the create-a-campaign process, locate and click 'Choose Suppression List'
2. Put a check in the box next to the list(s) you would like to include
3. Click the 'Ok' button
4. The selected suppression file name(s) will be visible when selected properly: