diff --git a/tests/auto/network/kernel/qdnslookup/tst_qdnslookup.cpp b/tests/auto/network/kernel/qdnslookup/tst_qdnslookup.cpp
index 20ecf8a6ab9..411975c31ad 100644
--- a/tests/auto/network/kernel/qdnslookup/tst_qdnslookup.cpp
+++ b/tests/auto/network/kernel/qdnslookup/tst_qdnslookup.cpp
@@ -556,7 +556,7 @@ void tst_QDnsLookup::setNameserverLoopback()
 
     // send an NXDOMAIN reply to release the lookup thread
     QByteArray reply = data;
-    reply[2] = 0x80;    // header->qr = true;
+    reply[2] = 0x80U;   // header->qr = true;
     reply[3] = 3;       // header->rcode = NXDOMAIN;
     server.writeDatagram(dgram.makeReply(reply));
     server.close();