How to delete an alert from the Logic Monitor UI

You should be able to set a custom threshold (blank blank blank) for that datasource instance. That should make that alert reset and never appear again.

In the new UI: http://help.logicmonitor.com/getting-started/i-just-signed-up-for-logicmonitor-now-what/7-tuning-alert-thresholds/

or old UI:

http://help.logicmonitor.com/using/i-got-an-alert-now-what/how-do-i-adjust-thresholds/