What I can tell from this is that the tenor did not create the SIP message;
ClientTransaction::ClientTransaction() failure encoding message
So there is something fundamentally wrong with either the software or the config. I am always concerned about the software because the SIP support in the A800 and A400 (Gen 1 units) is only beta (as described on Quintum’s web site). Since Quintum does not support the Gen 1 units anymore and will not be creating software for them, I am concerned that this beta software may have issues. I have heard of it working fine in some places and problems in others.
One thing to note is that you have both the register port and the proxy port the same, I believe, but not 100% that you need this to be different as they are different functions.