I am able to do an echo test.
I also found this documentation in self-help support:
https://www.obitalk.com/info/support/troubleshooting > Solid Green > “Unable to add device to OBiTALK”
I followed instructions for
* echo test
* updating firmware (now at 3.2.1 build 5757EX)
* modifying the DNS to 4.2.2.2
Unfortunately, I am still not able to register my device.