Configure siproxd to use behind a openvpn connection

Hello,

I need to configure a proxy-sip. I discovered siproxd, but I am not
able to use it.

My network is as follows:

PC-Windows -> Use MicroSip -> 192.168.1.10
PC-Linux -> Use siproxd ->
-->   Network interface -> ens33 -> 192.168.1.111
-->   Network interface -> tun0 ->  10.10.2.33 (OpenVPN raised)
PC-Asterisk -> 10.10.2.222

I use this configuration file for siproxd (the other default options)

if_inbound  = ens33
if_outbound = tun0
host_outbound = 10.10.2.222

In microsip, I configure the Proxy field and put: 192.168.1.111. The
other fields I leave them the same as when I have direct access to
PC-Asterisk (10.10.2.222) (or when I can use openvpn in this machine)

Microsip connects correctly, but does not allow me to make calls.

What am I doing wrong?

Thanks