diff --git a/core/lib/src/server.rs b/core/lib/src/server.rs
index fe5167ae78..50f1723bd1 100644
--- a/core/lib/src/server.rs
+++ b/core/lib/src/server.rs
@@ -114,7 +114,7 @@ impl Rocket<Orbit> {
             } else {
                 warn!("HTTP/3 cannot start without valid TCP/TLS configuration.");
                 info_!("Falling back to HTTP/1 and HTTP/2 server.");
-                self.clone().serve(listener).await?;
+                self.clone().serve12(listener).await?;
             }
         }
 
diff --git a/scripts/test.sh b/scripts/test.sh
index 434680225f..960027a4d0 100755
--- a/scripts/test.sh
+++ b/scripts/test.sh
@@ -128,6 +128,7 @@ function test_core() {
   FEATURES=(
     tokio-macros
     http2
+    http3
     secrets
     tls
     mtls