diff --git a/lib/diameter.py b/lib/diameter.py
index eef01cb..a8a6ac8f 100755
--- a/lib/diameter.py
+++ b/lib/diameter.py
@@ -2988,6 +2988,7 @@ def Answer_16777236_265(self, packet_vars, avps):
             imsi = None
             msisdn = None
             identifier = None
+            apnId = None
             try:
                 serviceUrn = bytes.fromhex(self.get_avp_data(avps, 525)[0]).decode('ascii')
             except: