fixed some things and tried to convert it into str

ServerNode/api.py

@@ -33,7 +33,7 @@ def add_sensordata():
         
     now = datetime.now()
     
-    timestamp = {"timestamp":now}
+    timestamp = {"timestamp":str(now)}
     
     sensordata.update(timestamp)
     

WorkerNode/NodeMCWifi/NodeMCWifi.ino

@@ -89,9 +89,9 @@ void loop() {
     DynamicJsonDocument doc(2048);
     // Add values in the document
     
-    doc["temperature"] = temperature;
+    doc["temperature"] = String(temperature);
-    doc["moisture"] = moisture;
+    doc["moisture"] = String(moisture);
-    doc["humidity"] = humidity;
+    doc["humidity"] = String(humidity);
 
     String requestBody;
     serializeJson(doc, requestBody);