diff --git a/src/flow-monitor/model/ipv4-flow-probe.cc b/src/flow-monitor/model/ipv4-flow-probe.cc
index aeb82f8b2..3df7cca9f 100644
--- a/src/flow-monitor/model/ipv4-flow-probe.cc
+++ b/src/flow-monitor/model/ipv4-flow-probe.cc
@@ -254,12 +254,12 @@ Ipv4FlowProbe::Ipv4FlowProbe (Ptr<FlowMonitor> monitor,
 
   std::ostringstream qd;
   qd << "/NodeList/" << node->GetId () << "/$ns3::TrafficControlLayer/RootQueueDiscList/*/Drop";
-  Config::ConnectWithoutContext (qd.str (), MakeCallback (&Ipv4FlowProbe::QueueDiscDropLogger, Ptr<Ipv4FlowProbe> (this)));
+  Config::ConnectWithoutContextFailSafe (qd.str (), MakeCallback (&Ipv4FlowProbe::QueueDiscDropLogger, Ptr<Ipv4FlowProbe> (this)));
 
   // code copied from point-to-point-helper.cc
   std::ostringstream oss;
   oss << "/NodeList/" << node->GetId () << "/DeviceList/*/TxQueue/Drop";
-  Config::ConnectWithoutContext (oss.str (), MakeCallback (&Ipv4FlowProbe::QueueDropLogger, Ptr<Ipv4FlowProbe> (this)));
+  Config::ConnectWithoutContextFailSafe (oss.str (), MakeCallback (&Ipv4FlowProbe::QueueDropLogger, Ptr<Ipv4FlowProbe> (this)));
 }
 
 Ipv4FlowProbe::~Ipv4FlowProbe ()
diff --git a/src/flow-monitor/model/ipv6-flow-probe.cc b/src/flow-monitor/model/ipv6-flow-probe.cc
index b509e472f..1ed7284de 100644
--- a/src/flow-monitor/model/ipv6-flow-probe.cc
+++ b/src/flow-monitor/model/ipv6-flow-probe.cc
@@ -224,12 +224,12 @@ Ipv6FlowProbe::Ipv6FlowProbe (Ptr<FlowMonitor> monitor,
 
   std::ostringstream qd;
   qd << "/NodeList/" << node->GetId () << "/$ns3::TrafficControlLayer/RootQueueDiscList/*/Drop";
-  Config::ConnectWithoutContext (qd.str (), MakeCallback (&Ipv6FlowProbe::QueueDiscDropLogger, Ptr<Ipv6FlowProbe> (this)));
+  Config::ConnectWithoutContextFailSafe (qd.str (), MakeCallback (&Ipv6FlowProbe::QueueDiscDropLogger, Ptr<Ipv6FlowProbe> (this)));
 
   // code copied from point-to-point-helper.cc
   std::ostringstream oss;
   oss << "/NodeList/" << node->GetId () << "/DeviceList/*/TxQueue/Drop";
-  Config::ConnectWithoutContext (oss.str (), MakeCallback (&Ipv6FlowProbe::QueueDropLogger, Ptr<Ipv6FlowProbe> (this)));
+  Config::ConnectWithoutContextFailSafe (oss.str (), MakeCallback (&Ipv6FlowProbe::QueueDropLogger, Ptr<Ipv6FlowProbe> (this)));
 }
 
 /* static */