This error appear while trying to deploy agent for Enterprise manager 12c (em12c) and the cause for this error that port 3872 is already in use :
solution
[root@em12c Middleware]# netstat -anp | grep 3872
tcp 0 0 :::3872 :::* LISTEN 2391/java
[root@em12c Middleware]# kill -9 2391
[root@em12c Middleware]# netstat -anp | grep 3872
Deploy Again
Thank you
Osama Mustafa