As a follow up question to this, are you somehow starting the EMS prior to the network interfaces becoming available? Are you changing your network configuration on the fly? I ask because there is only a very specific time where we ahve seen this issue before. The issue is that by default, in linux, a TCP connection will be established and used for DNS lookups. That TCP connection is then maintained and used for subsequent DNS lookups. This is almost never an issue because the first time it establishes the connection, the DNS will succeed and you are good to go. (Or the tcp connection cant be made and it waits for a valid network interface).
We have made a change very recently that moves the DNS to a UDP based lookup and resolves this issue, but it is a bit less efficient.
The change should be migrated to the release branch soon and we can get you an updated build if you like. In the mean-time I’d be curious to know about the timing of the setup of your network interfaces.