diff --git a/xos/synchronizers/vcpe/steps/sync_vcpetenant.py b/xos/synchronizers/vcpe/steps/sync_vcpetenant.py
index 21b5bd7..cd8a292 100644
--- a/xos/synchronizers/vcpe/steps/sync_vcpetenant.py
+++ b/xos/synchronizers/vcpe/steps/sync_vcpetenant.py
@@ -150,7 +150,7 @@
             wan_vm_mac = parts[2]
         else:
             if CORD_USE_VTN:
-                raise Exception("no vm_wan_addr tag for instance %s" % instance)
+                raise Exception("no vm_wan_addr tag for instance %s" % o.instance)
 
         fields = {"vlan_ids": vlan_ids,   # XXX remove this
                 "s_tags": s_tags,