diff --git a/lib/call-session.js b/lib/call-session.js
index f503d37..ee1cd14 100644
--- a/lib/call-session.js
+++ b/lib/call-session.js
@@ -7,7 +7,7 @@ const {SipError, stringifyUri, parseUri} = require('drachtio-srf');
 const debug = require('debug')('jambonz:sbc-outbound');
 
 const makeInviteInProgressKey = (callid) => `sbc-out-iip${callid}`;
-const IMMUTABLE_HEADERS = ['via', 'from', 'to', 'call-id', 'cseq', 'max-forwards', 'content-length'];
+const IMMUTABLE_HEADERS = ['via', 'from', 'to', 'call-id', 'cseq', 'max-forwards', 'content-length', 'contact'];
 /**
  * this is to make sure the outgoing From has the number in the incoming From
  * and not the incoming PAI
@@ -16,6 +16,7 @@ const createBLegFromHeader = (req, teams, register_from_domain = null) => {
   const from = req.getParsedHeader('From');
   const uri = parseUri(from.uri);
   let user = uri.user || 'anonymous';
+  this.scheme = uri.scheme;
   let host = 'localhost';
   if (teams) {
     host = req.get('X-MS-Teams-Tenant-FQDN');
@@ -1057,8 +1058,6 @@ Duration=${payload.duration} `
         if (farEnd.params?.transport) {
           this.transport = `transport=${farEnd.params.transport}`;
         }
-        /* TODO: we receive a lowercase 'contact' from feature-server */
-        delete customHeaders['contact'];
 
         this.referContactHeader = `<${this.scheme}:${uri.user}@${uri.host}:${uri.port}>;${this.transport}`;
         const response = await this.uac.request({