diff --git a/proxy/shadowsocks/protocol.go b/proxy/shadowsocks/protocol.go
index 98e9b188c..ceec76f00 100644
--- a/proxy/shadowsocks/protocol.go
+++ b/proxy/shadowsocks/protocol.go
@@ -117,7 +117,8 @@ func ReadRequest(reader io.Reader, auth *Authenticator, udp bool) (*Request, err
 	if request.OTA {
 		actualAuth := auth.Authenticate(nil, buffer.Value[0:lenBuffer])
 		if !serial.BytesLiteral(actualAuth).Equals(serial.BytesLiteral(authBytes)) {
-			log.Error("Shadowsocks: Invalid OTA: ", actualAuth)
+			log.Debug("Shadowsocks: Invalid OTA. Expecting ", actualAuth, ", but got ", authBytes)
+			log.Warning("Shadowsocks: Invalid OTA.")
 			return nil, proxy.ErrorInvalidAuthentication
 		}
 	}