You have an upcoming event and you have been unsuccessfully been able to "confirm" the event on the Marketing Event Calendar.
Only batch assets can be "confirmed"/approved on the Marketing Event Calendar.
If the error displays "Invalid Campaign" - check the campaign that you are trying to confirm. If it is a Trigger Campaign, that is why it's unable to be confirmed.
Batch assets include Batch Campaigns, as well as Email Batch Programs.
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