I'm trying to use the push proxy with Plivo however apparently the Zoiper push proxy is rejecting the incoming calls from the Plivo server, causing a "Routing Error" message from Plivo. I've contacted Plivo support and they told me that this message is caused by the proxy not accepting the call request from the Plivo server.
I've tried changing the Push transport and Proxy protocols to all different settings but calls still do not go through. In all cases, the account shows as "registered".
Unless a solution is found soon, I'll cancel my proxy subscription.