The subject line for an email sent out to leads did not match what was set for an approved email.
The email may have Dynamic Subject Lines enabled. Dynamic Subject Lines allow you to set dynamic content for the subject line based on the Segmentation of your leads. Visit our Documentation for further information about segments and dynamic content.
The issue can be resolved by converting the subject line to a Static Subject Line. A Static Subject Line is a single line of content that will send out to any recipient of your email, regardless of their segmentation. You can do so by doing the following:
Click on the Subject Line to bring up the Subject Line edit buttons.