When creating and sending a new Email Campaign, you may receive the following error message when advancing to the Confirm & Send step.
To get around this error, the workaround is to create a filter to exclude any contacts who aren't subscribed to a mailing list.
First, from the left navigation head to Filters > Add Filter to build a filter for subscribed contacts only. See below for what those conditions should look like.
Name your filter "Subscribers Only" (or something similar) > Save.
Next, apply the filter to a new Email Campaign by selecting Advanced Search > Advanced Filters. Locate the "Subscribers Only" filter > Apply.
