There are two possible reasons why your e-mails are blocked or missing.  Either your seed list is not updated or your e-mails were blocked and deleted by one or more providers, with the result that your e-mails were even not sent to the spam folder.

In this case, first check the detail view of the ISP deliverability tracking function to see which ISPs blocked your e-mails. Next, to determine exactly how many of your recipients are affected by this problem, check your recipients list. If only a few are involved, the blocking is of only marginal importance.

Note: Delivery Watch weights each monitored ISP or Webmail provider using the same statistical values. However, the actual proportional relationship between the various ISPs is determined by your own recipients list. Hence, you will have to ascertain the proportion of your recipients that receive their mail via an ISP that blocked your e-mails.