Phone accross IPSEC VPN

I am running Asterisk on a ClearOS gateway with an IPSEC VPN to a remote location where I have a phone, and whenever that phone tries to login, I am getting:

[May 26 11:20:35] WARNING[25638] chan_sip.c: sip_xmit of 0xb7a05fc8 (len 528) to returned -1: No such process

in the log file.

I have setup as a localnet in sip_nat.conf

Any ideas?