diff --git a/bin/tests/system/mkeys/ns5/named.conf.in b/bin/tests/system/mkeys/ns5/named.conf.in
index f2eb35d787..6314888979 100644
--- a/bin/tests/system/mkeys/ns5/named.conf.in
+++ b/bin/tests/system/mkeys/ns5/named.conf.in
@@ -24,6 +24,7 @@ options {
 	dnssec-enable yes;
 	dnssec-validation auto;
 	bindkeys-file "managed.conf";
+	servfail-ttl 0;
 };
 
 key rndc_key {