diff --git a/wled00/presets.cpp b/wled00/presets.cpp
index a1a7b08fc..80335ad3b 100644
--- a/wled00/presets.cpp
+++ b/wled00/presets.cpp
@@ -83,7 +83,7 @@ static void doSaveState() {
 
 bool getPresetName(byte index, String& name)
 {
-  if (!requestJSONBufferLock(9)) return false;
+  if (!requestJSONBufferLock(19)) return false;
   bool presetExists = false;
   if (readObjectFromFileUsingId(getFileName(), index, pDoc))
   {
diff --git a/wled00/util.cpp b/wled00/util.cpp
index ea89adc68..9e7d2eb46 100644
--- a/wled00/util.cpp
+++ b/wled00/util.cpp
@@ -215,10 +215,10 @@ bool requestJSONBufferLock(uint8_t module)
   }
   unsigned long now = millis();
 
-  while (jsonBufferLock && millis()-now < 1000) delay(1); // wait for a second for buffer lock
+  while (jsonBufferLock && millis()-now < 100) delay(1); // wait for fraction for buffer lock
 
-  if (millis()-now >= 1000) {
-    DEBUG_PRINT(F("ERROR: Locking JSON buffer failed! ("));
+  if (jsonBufferLock) {
+    DEBUG_PRINT(F("ERROR: Locking JSON buffer failed! (still locked by "));
     DEBUG_PRINT(jsonBufferLock);
     DEBUG_PRINTLN(")");
     return false; // waiting time-outed
diff --git a/wled00/wled_serial.cpp b/wled00/wled_serial.cpp
index c6e984035..9cca09db0 100644
--- a/wled00/wled_serial.cpp
+++ b/wled00/wled_serial.cpp
@@ -113,7 +113,10 @@ void handleSerial()
 
         } else if (next == '{') { //JSON API
           bool verboseResponse = false;
-          if (!requestJSONBufferLock(16)) return;
+          if (!requestJSONBufferLock(16)) {
+            Serial.println(F("{\"error\":3}")); // ERR_NOBUF
+            return;
+          }
           Serial.setTimeout(100);
           DeserializationError error = deserializeJson(*pDoc, Serial);
           if (error) {
diff --git a/wled00/wled_server.cpp b/wled00/wled_server.cpp
index 1de200218..0e20aaf53 100644
--- a/wled00/wled_server.cpp
+++ b/wled00/wled_server.cpp
@@ -285,7 +285,10 @@ void initServer()
     bool verboseResponse = false;
     bool isConfig = false;
 
-    if (!requestJSONBufferLock(14)) return;
+    if (!requestJSONBufferLock(14)) {
+      serveJsonError(request, 503, ERR_NOBUF);
+      return;
+    }
 
     DeserializationError error = deserializeJson(*pDoc, (uint8_t*)(request->_tempObject));
     JsonObject root = pDoc->as<JsonObject>();
diff --git a/wled00/ws.cpp b/wled00/ws.cpp
index 2bf74a41f..1dd141a68 100644
--- a/wled00/ws.cpp
+++ b/wled00/ws.cpp
@@ -36,7 +36,10 @@ void wsEvent(AsyncWebSocket * server, AsyncWebSocketClient * client, AwsEventTyp
         }
 
         bool verboseResponse = false;
-        if (!requestJSONBufferLock(11)) return;
+        if (!requestJSONBufferLock(11)) {
+          client->text(F("{\"error\":3}")); // ERR_NOBUF
+          return;
+        }
 
         DeserializationError error = deserializeJson(*pDoc, data, len);
         JsonObject root = pDoc->as<JsonObject>();
@@ -101,7 +104,14 @@ void sendDataWs(AsyncWebSocketClient * client)
   if (!ws.count()) return;
   AsyncWebSocketMessageBuffer * buffer;
 
-  if (!requestJSONBufferLock(12)) return;
+  if (!requestJSONBufferLock(12)) {
+    if (client) {
+      client->text(F("{\"error\":3}")); // ERR_NOBUF
+    } else {
+      ws.textAll(F("{\"error\":3}")); // ERR_NOBUF
+    }
+    return;
+  }
 
   JsonObject state = pDoc->createNestedObject("state");
   serializeState(state);
@@ -109,7 +119,7 @@ void sendDataWs(AsyncWebSocketClient * client)
   serializeInfo(info);
 
   size_t len = measureJson(*pDoc);
-  DEBUG_PRINTF("JSON buffer size: %u for WS request (%u).\n", pDoc->memoryUsage(), len);
+  DEBUG_PRINTF_P(PSTR("JSON buffer size: %u for WS request (%u).\n"), pDoc->memoryUsage(), len);
 
   size_t heap1 = ESP.getFreeHeap();
   DEBUG_PRINT(F("heap ")); DEBUG_PRINTLN(ESP.getFreeHeap());