SIP2SIP

I have $20 credits but unable to make PSTN calls to anywhere, tried to US and UAE phone numbers.
Could you please fix this. I am using SIP client: Telephone.app (PJSIP) on Mac OS X.

SIP/2.0 403 PSTN calls are forbidden
Via: SIP/2.0/UDP 10.200.25.4:54534;received=162.211.YYY.XX;rport=54534;branch=z9hG4bKPjWkck1Tr-bhSQyC5L5XqEQKaipBskVwuk
From: "Anthony" <sip:xxxxxx@sip2sip.info>;tag=Px1V27AfazZqu7KKf7j-pefVozTZLbkN
To: <sip:+97150YYY7XXX@sip2sip.info>;tag=f2f36c970cbb772c79daadc5c9d6e415.3059
Call-ID: pHyl0AitQHPZLgUeDcomjXKfajehv1rD
CSeq: 23315 INVITE
Server: SIP Thor on OpenSIPS XS 1.9.0
Content-Length: 0

• Please check the Call-ID for reference.