If a promotion has ended, and the promotion message is still appearing, as below:
You will need to remove the message using the steps below:
Select the envelope (last icon on the right in the below screenshot)
Double click on Setup User Messages
In this screen is where you can add user messages:
On the above screenshot, click on the folder icon in the top left corner, to view and remove messages.
The below screen will appear:
Select the message row that you want to delete or edit, and click the relevant button (Delete or Edit Message)