Thanks for your reply Drgeoff !!
Yes, I'm using the local interface.
Yes, I've disabled Obitalk Provisioning.
Yes, the 110 does have the latest 2886 firmware (not NAF).
The guide you mentioned comes after where it says:
"Once you have finished changing all those settings, click on the button Submit to save the changes and reboot your OBi device, your device should now be registered."
Is unknown to me - 1st I've seen of it.
I did all the steps very carefully - multiple times & even factory reset the 110:
https://wiki.voip.ms/article/OBi_100/110_%26_OBi_200I stopped before where it says how to do it with call encryption TLS/SRTP.
Even their tech support was baffled - no matter what, still the 403 error.
Changing the PW, main account or sub-account, all to the same result.
So...do you suggest I now try the call encryption TLS/SRTP stuff ??
Thanks Again !!