IAXagent 0.7.0 Settings?

I have an Android phone I’m trying to get up and running on an IAX2 extention.
I’ve been abale to confirm the extention is configured correctly, using Zoiper on my laptop.

But, the only IAX app for Android I can find is IAXagent, which seems to fail immediately when I try to register it.
Am I doing something wrong with these settings?

User: {my extention number}
Password: {secret word in the extention config}
Domain/Server: {my dyndns address}

Caller ID
(Left Name & Extention alone for now.)

Proximity Sensor: Enabled
Log call records: Enabled
(All other’s disabled.)

Audio Codec
(All enabled, with GSM default.)