Collector not MOM sending alerts

Products

• CA Application Performance Management Agent (APM / Wily / Introscope)
• INTROSCOPE

Issue/Introduction

The Collectors are trying to send alerts/actions instead of the MOM. The /var/spool/mqueue directory is filling up the /var directory with email messages.

What properties should be checked on the MOM and collectors? Why would the collectors be trying to send out messages? 

Environment

Issue was found in APM 10.3 but could impact any supported release

Cause

   A Management Module was mistakenly placed on the Collector causing the alert actions. 

Resolution

1) Remove the management module jar from all the collectors. Then restart the Collector
2) Mqueue files are emails to remote locations . To remove these files see links like the following. 
https://www.linuxquestions.org/questions/linux-general-1/delete-files-in-var-spool-mqueue-439030/ https://community.hpe.com/t5/General/Help-in-clearing-out-var-spool-mqueue/td-p/5276091 or any other approach to clear the mail