diff --git a/lib/call-session.js b/lib/call-session.js
index a101eab..90f2269 100644
--- a/lib/call-session.js
+++ b/lib/call-session.js
@@ -19,6 +19,9 @@ const debug = require('debug')('jambonz:sbc-inbound');
 const MS_TEAMS_USER_AGENT = 'Microsoft.PSTNHub.SIPProxy';
 const MS_TEAMS_SIP_ENDPOINT = 'sip.pstnhub.microsoft.com';
 const IMMUTABLE_HEADERS = ['via', 'from', 'to', 'call-id', 'cseq', 'max-forwards', 'content-length'];
+const NONCOPYABLE_RESPONSE_HEADERS = [
+  'via', 'from', 'to', 'call-id', 'cseq', 'contact', 'content-length', 'content-type'
+];
 
 /**
  * this is to make sure the outgoing From has the number in the incoming From
@@ -281,6 +284,7 @@ class CallSession extends Emitter {
         proxy,
         headers,
         responseHeaders,
+        passFailure: false,
         proxyRequestHeaders: [
           'all',
           '-Authorization',
@@ -355,12 +359,16 @@ class CallSession extends Emitter {
         this.stats.increment('sbc.terminations', tags);
         this.logger.info(`call failed to connect to feature server with ${err.status}`);
 
-        /* capture trace_id from the feature server's error response for the CDR */
+        /* capture trace_id and application_sid from the feature server's error response for the CDR. */
         if (this.req.locals.cdr && err.res) {
           const trace_id = err.res.get('X-Trace-ID');
           if (trace_id) {
             this.req.locals.cdr.trace_id = trace_id;
           }
+          const application_sid = err.res.get('X-Application-Sid');
+          if (application_sid) {
+            this.req.locals.cdr.application_sid = application_sid;
+          }
         }
 
         this.emit('failed');
@@ -377,6 +385,22 @@ class CallSession extends Emitter {
           .catch((err) => this.logger.error(err, 'Error decrementing call counts'));
 
       }
+
+      /* manually proxy the failure response to UAS so that the trace_id/application_sid capture above runs before
+         res.end fires (which is what triggers the failure-CDR writer). */
+      if (err.message !== 'call canceled' && !this.res.finalResponseSent) {
+        if (err instanceof SipError && err.res) {
+          const headers = {};
+          Object.keys(err.res.headers || {}).forEach((h) => {
+            if (!NONCOPYABLE_RESPONSE_HEADERS.includes(h)) headers[h] = err.res.headers[h];
+          });
+          this.res.send(err.status, err.reason, {headers});
+        }
+        else {
+          this.res.send(err.status || 500, err.reason);
+        }
+      }
+
       this.srf.endSession(this.req);
     }
   }
diff --git a/lib/middleware.js b/lib/middleware.js
index 25c982e..f397077 100644
--- a/lib/middleware.js
+++ b/lib/middleware.js
@@ -31,7 +31,6 @@ module.exports = function(srf, logger) {
     queryCallLimits,
   }  = srf.locals.dbHelpers;
   const {stats, writeCdrs, lookupAuthCarriersForAccountAndSP, getApplicationForDidAndCarrier} = srf.locals;
-  const {retrieveKey} = srf.locals.realtimeDbHelpers;
 
   const initLocals = (req, res, next) => {
     const callId = req.get('Call-ID');
@@ -60,32 +59,16 @@ module.exports = function(srf, logger) {
 
     /* write cdr for non-success response here */
     res.once('end', ({status}) => {
-      if (req.locals.cdr && req.locals.cdr.account_sid && status > 200  && 401 !== status) {
-        const writeCdr = () => {
-          const trunk = ['trunk', 'teams'].includes(req.locals.originator) ?
-            req.locals.carrier : req.locals.originator;
-          writeCdrs({...req.locals.cdr,
-            terminated_at: Date.now(),
-            termination_reason: status === 487 === status ? 'caller abandoned' : 'failed',
-            sip_status: status,
-            trunk,
-            ...(req.locals.application_sid && {application_sid: req.locals.application_sid})
-          }).catch((err) => logger.error({err}, 'Error writing cdr for call failure'));
-        };
-
-        /* if trace_id is missing, look it up from Redis using the original Call-ID */
-        if (!req.locals.cdr.trace_id) {
-          retrieveKey(`callid:${callId}`)
-            .then((trace_id) => {
-              if (trace_id) req.locals.cdr.trace_id = trace_id;
-              return;
-            })
-            .catch((err) => logger.debug({err, callId}, 'Error retrieving trace_id from Redis'))
-            .finally(() => writeCdr())
-            .catch(() => {});
-        } else {
-          writeCdr();
-        }
+      if (req.locals.cdr && req.locals.cdr.account_sid && status > 200 && 401 !== status) {
+        const trunk = ['trunk', 'teams'].includes(req.locals.originator) ?
+          req.locals.carrier : req.locals.originator;
+        writeCdrs({...req.locals.cdr,
+          terminated_at: Date.now(),
+          termination_reason: status === 487 ? 'caller abandoned' : 'failed',
+          sip_status: status,
+          trunk,
+          ...(req.locals.application_sid && {application_sid: req.locals.application_sid})
+        }).catch((err) => logger.error({err}, 'Error writing cdr for call failure'));
       }
     });