"Send email to subscribers" in the test configuration page allows you to be notified when a test completes, either successfully or failed.
However you may want to be notified only if tests fail, especially with tests running frequently. How can this be accomplished?
Blazemeter Saas Performance and Functional testing
You can setup a Workspace alert as explained in this article and configure it to alert only when tests fail or tests end without data:
When you disable the "send email to subscribers" switch in the left pane of the test configuration page, it should accomplish what you are after.
Be aware however that the Workspace Alert applies to ALL tests in that workspace!