diff --git a/tests/unit-tests/utils/tracers/ndn-app-delay-tracer.t.cpp b/tests/unit-tests/utils/tracers/ndn-app-delay-tracer.t.cpp
index 66e90a6..0f24b80 100644
--- a/tests/unit-tests/utils/tracers/ndn-app-delay-tracer.t.cpp
+++ b/tests/unit-tests/utils/tracers/ndn-app-delay-tracer.t.cpp
@@ -39,7 +39,7 @@
     // setting default parameters for PointToPoint links and channels
     Config::SetDefault("ns3::PointToPointNetDevice::DataRate", StringValue("10Mbps"));
     Config::SetDefault("ns3::PointToPointChannel::Delay", StringValue("10ms"));
-    Config::SetDefault("ns3::DropTailQueue::MaxPackets", StringValue("20"));
+    Config::SetDefault("ns3::QueueBase::MaxPackets", UintegerValue(20));
 
     createTopology({
         {"1", "2"},