OK, but the extension you are sending it to isn't available to the inbound route. Double check your extension setup and make sure you haven't mistyped something. The fact that the phone works is encouraging, but this is a common problem that is usually caused by the vagaries of Chan-SIP and PJ-SIP.
The /var/log/asterisk/full log file should show the steps the inbound call is taking, so you might want to look at that and see where the error is getting generated.
For testing, try setting the inbound route to something that isn't variable, like a voicemail destination or an announcement. This way, you can debug the process step-by-step.