diff --git a/lib/call-session.js b/lib/call-session.js
index 76c5f99..b8351a4 100644
--- a/lib/call-session.js
+++ b/lib/call-session.js
@@ -322,7 +322,7 @@ class CallSession extends Emitter {
               const prefix = vc.tech_prefix || '';
               const transport =  o.protocol?.startsWith('tls') ? 'tls' : (o.protocol || 'udp');
               const hostport = !o.port || 5060 === o.port ? o.ipv4 : `${o.ipv4}:${o.port}`;
-              const prependPlus = vc.e164_leading_plus && /^[1-9]/.test(this.req.calledNumber) ? '+' : '';
+              const prependPlus = vc.e164_leading_plus && /^[1-9]/.test(calledNumber) ? '+' : '';
               const scheme = transport === 'tls' && !process.env.JAMBONES_USE_BEST_EFFORT_TLS && o.use_sips_scheme ?
                 'sips' : 'sip';
               let u = `${scheme}:${prefix}${prependPlus}${calledNumber}@${hostport};transport=${transport}`;