Initial setup - UPDC updates and nothing else

[tgryphon]

Forgive me for being confused or potentially missing an instruction step.

Running latest image on a Docker container on a Synology NAS.
Both the NAS and the JuiceBox have static IPs.
I'm using the UPDATE_UDPC method, which per terminal logs seems to be working.

However, that's all that's working; as I'm getting:

WARNING [juicebox_mitm] No Message Received after 120sec. (TimeoutError: )
WARNING [juicebox_mitm] JuiceboxMITM Reconnecting.

This repeats basically every 120 seconds, between UDPC updates.