On analysis, you see that the agend agent indeed refuses any connections:
[E1JSchreiber@phl21240-db03 ~]$ telnet phl21240-db03.qa.dc.XXX.hh 20910 Trying 10.120.40.108... telnet: connect to address 10.120.40.108: Connection refused [E1JSchreiber@phl21240-db03 ~]$ telnet 127.0.0.1 20910 Trying 127.0.0.1... Connected to 127.0.0.1.
Reason for this might be that the Agents network interface is configured to (only) use localhost. This is caused by selecting localhost, which is default, when creating the agend using config.sh. Correct is selecting "All local addresses" for "Server Listen Address".
To correct the settings afterwards, you can modify <...>/Middleware/user_projects/domains/base_domain/config/fmwconfig/components/system-comp-config.xml and configure the agents hosts fqdn name as <listen-address> instead of "localhost".