diff --git a/common/httpx/httpx.go b/common/httpx/httpx.go
index 039f4c4c..ecbc4c66 100644
--- a/common/httpx/httpx.go
+++ b/common/httpx/httpx.go
@@ -183,6 +183,10 @@ func New(options *Options) (*HTTPX, error) {
 		CheckRedirect: redirectFunc,
 	}, retryablehttpOptions)
 
+	if httpx.Options.Protocol == "http11" {
+		httpx.client.HTTPClient2 = nil
+	}
+
 	transport2 := &http2.Transport{
 		TLSClientConfig: &tls.Config{
 			InsecureSkipVerify: true,
diff --git a/common/httpx/httpx_test.go b/common/httpx/httpx_test.go
index 7da6ad12..be22a85b 100644
--- a/common/httpx/httpx_test.go
+++ b/common/httpx/httpx_test.go
@@ -28,3 +28,13 @@ func TestDo(t *testing.T) {
 		require.Greater(t, len(resp.Raw), 800)
 	})
 }
+
+func TestHTTP11ShouldDisableRetryableHTTP2Fallback(t *testing.T) {
+	opts := DefaultOptions
+	opts.Protocol = "http11"
+
+	ht, err := New(&opts)
+	require.NoError(t, err)
+
+	require.Nil(t, ht.client.HTTPClient2, "when protocol is http11, retryablehttp HTTPClient2 fallback should be disabled")
+}