Failed to start Voice Response node

The Blueworx Voice Response VRBE interface can fail to start with:

A message in DTstatus.out:

Starting the HostManager…
The process ID of the HostManager is XXXXX
The HostManager failed to start after 60s.
Please check for any error messages.

An error entry of error_id 21004 in errorlog:

DTBE Failed to start Websphere Voice Response node.
sequence  = xxx     csec      = xx    error_id  = 21004

Even though all of the configured Blueworx Voice Response Java nodes (defined in default.cff) are local, Java RMI still uses the TCP/IP stack for communication and hostname resolution. This problem can occur if the system is set up to use DNS for hostname resolution and either the DNS server is not responding, or the DNS resolves to the wrong hostname or IP address.

If the system is configured to use DNS, check the file /etc/resolv.conf for the list of DNS servers. If any of these DNS servers, especially the first one on the list, are not responding, change the TCP/IP setup to use a working DNS server.

Failed to start Voice Response node - error_id 21004