When sending a mass email you may encounter an error on step 4 which states: You Have Exceeded Your Mass Email Subscription.Your organization's subscription enables you to send X emails this month but it has already send X. Please contact firstname.lastname@example.org if you would like to discuss increasing your monthly limit.
Depending on if you are sending an Advanced or Basic Mass Email your subscription may be different. It's possible that you sent more than your subscription allows because the last mailing pushed you over the limit but eTapestry chose to finish sending all of the emails for you as a courtesy.
Please reach out to sales@eTapestry.com or your account executive at eTapClientAccountExecs@blackbaud.com to ask about purchasing additional emails.