Ha ha, indeed. I had to ask, ya know, given your user name "sparkie".
That points the finger at the OBi box. It it brand new, or did you get it second-hand? Has it ever worked? Have you made any configuration changes beyond the factory defaults? If you did, then you might want to try removing it from the OBiTALK portal, performing a factory reset, and setting it up again.
Other than that, there are some settings to increase the ring voltage and change the AC ring waveform from sinusoidal to trapezoidal. A few phones respond to one waveform but not the other.
On the OBiTALK portal, get into Expert mode, and go to Physical Interfaces --> Phone
I don't have a OBi 1xx box connected at the moment, but on a 202, it looks like my attached screenshot. Uncheck both of the check boxes to change the settings.
If that doesn't help, then it's time to open a ticket with Obihai to get it (and its power adapter) replaced.