Collector keeps dying trying to connect to Performance Analysis Agent (4337128)

Error occurred while trying to connect to Performance Analysis Agent  
Collector keeps dying  
/agent/log/activity.log (on Monitored Host) file shows multiple MW that sample the same collector, like:
StealthCollect@6.0@quest_sc_collector@Collector1-Instance1 (2211972) killed by quest (USER1@MW1)
StealthCollect@6.0@quest_sc_collector@Collector1-Instance1 started
StealthCollect@6.0@quest_sc_collector@Collector1-Instance1 (1999062) killed by quest (USER2@MW2)  
In SQL Server, collector error logs show: "Performing emergency exit due to signal 2"
stderr.quest_sc_collector.1: Performing emergency exit due to signal 2 (includes all preceding logs where Collector restart has occured, eg. 3,4,5, etc.)

More than one Middleware server is configured to connect to the same Collector.

Choose one Middleware server to manage that Collector...
- Remove the Middleware installation from the erroneous Middleware server
- Stop the MW processes on the erroneous MW server. Disable the processes that relate to the problem Collector to prevent restart after reboot.