This issue can be caused by there being no email address to send the alert to.
Log in to TaskCentre, then double-click the affected task.
Double-click the **SMTP step**.
Check if there is an email address listed. If not, the address needs to be added to the step.
If the email address comes from the **RecordSet** (from the ODBC step), check whether the query is returning an email address.
Close the SMTP step window.
Double-click the **ODBC step**.
Click the **Lightning Bolt** icon to run the query, then click the **Results** tab.
Check whether any email addresses in the results are blank.
If email addresses are blank, investigate the SQL query (for example, using SQL Management Studio) to find where the email address is sourced from, then populate the field correctly. If all email addresses are correct, the issue may be with the mail server being unavailable — check the mail server and try running the task again.