Relay slave fails to connect over Amazon ELB

Trying to configure a slave Icecast server through an Amazon Elastic Load Balancer (ELB), the socket never connects. Log shows this error: WARN slave/update_from_master Relay slave failed to contact master server to fetch stream list

using strace it seems like the connection never establishes on the socket's opening level, but there is not description of the exact error.

Replacing the load balancer DNS with the IP of one of the servers that are behind the ELB does seems to work.

login as the icecast user I was able to verify that the same information does work directly via telnet and curl. Only the icecast connection fails through the ELB.