Registration doesn't seem to work

[ymhee_bcex]

I have a Premium account and I am trying to set up incoming calls from my VSP (TiVi - Sveiks). I set it up successfully in X-Lite, to make sure that there are no problems with VSP and with what I am doing.

Additionally, the calls through SIP broker to my Voxalot number have no problems, either.

The provider in VSP screen shows as registered; however, when I call in, I am getting fast busy signal. Important, that when I register FWD, everything seems to work OK. (yes, I turn off FWD registration when I turn on TiVi registration - in fact, I turned on FWD only for troubleshooting).

So, it looks like the problem is somewhere between TiVi and Voxalot. TiVi says that since X-lite and ATA work fine - they don't see any problem on their side. Obviously, since FWD is working fine, too - it's not generic Voxalot problem, either. Is there anything you can suggest to troubleshoot this problem further?

TIA
Felix