diff --git a/sensorhub-service-consys/src/main/java/org/sensorhub/impl/service/consys/RestApiServlet.java b/sensorhub-service-consys/src/main/java/org/sensorhub/impl/service/consys/RestApiServlet.java
index d2473d7a2..403ce9226 100644
--- a/sensorhub-service-consys/src/main/java/org/sensorhub/impl/service/consys/RestApiServlet.java
+++ b/sensorhub-service-consys/src/main/java/org/sensorhub/impl/service/consys/RestApiServlet.java
@@ -51,7 +51,7 @@ public abstract class RestApiServlet extends HttpServlet
 {
     static final String LOG_REQUEST_MSG = "{} {}{} (from ip={}, user={})";
     static final String INTERNAL_ERROR_MSG = "Internal server error";
-    static final String INTERNAL_ERROR_LOG_MSG = INTERNAL_ERROR_MSG + " while processing request " + LOG_REQUEST_MSG;
+    static final String ERROR_LOG_MSG = "{} while processing request " + LOG_REQUEST_MSG;
     static final String ACCESS_DENIED_ERROR_MSG = "Permission denied";
     static final String JSON_CONTENT_TYPE = "application/json";
 
@@ -379,18 +379,24 @@ public Object createWebSocket(ServletUpgradeRequest req, ServletUpgradeResponse
     protected void logRequest(HttpServletRequest req)
     {
         if (log.isInfoEnabled())
-            logRequestInfo(req, null);
+            logRequestInfo(req, null, null);
     }
     
     
     protected void logError(HttpServletRequest req, Throwable e)
+    {
+        logError(req, null, e);
+    }
+    
+    
+    protected void logError(HttpServletRequest req, String error_prefix, Throwable e)
     {
         if (log.isErrorEnabled())
-            logRequestInfo(req, e);
+            logRequestInfo(req, error_prefix, e);
     }
     
     
-    protected void logRequestInfo(HttpServletRequest req, Throwable error)
+    protected void logRequestInfo(HttpServletRequest req, String error_prefix, Throwable error)
     {
         String method = req.getMethod();
         String url = req.getRequestURI();
@@ -416,7 +422,7 @@ protected void logRequestInfo(HttpServletRequest req, Throwable error)
             query = "?" + req.getQueryString();
         
         if (error != null)
-            log.error(INTERNAL_ERROR_LOG_MSG, method, url, query, ip, user, error);
+            log.error(ERROR_LOG_MSG, error_prefix, method, url, query, ip, user, error);
         else
             log.info(LOG_REQUEST_MSG, method, url, query, ip, user);
     }
@@ -459,8 +465,8 @@ public void sendError(int code, String msg, HttpServletRequest req, HttpServletR
     
     protected void handleInvalidRequestException(HttpServletRequest req, HttpServletResponse resp, InvalidRequestException e)
     {
-        log.debug("Invalid request ({}): {}", e.getErrorCode(), e.getMessage());
-        
+        logError(req, String.format("Invalid request (%s)", e.getErrorCode()), e);
+
         switch (e.getErrorCode())
         {
             case UNSUPPORTED_OPERATION:
diff --git a/sensorhub-service-consys/src/main/java/org/sensorhub/impl/service/consys/ServiceErrors.java b/sensorhub-service-consys/src/main/java/org/sensorhub/impl/service/consys/ServiceErrors.java
index 14b53ef87..3150bba63 100644
--- a/sensorhub-service-consys/src/main/java/org/sensorhub/impl/service/consys/ServiceErrors.java
+++ b/sensorhub-service-consys/src/main/java/org/sensorhub/impl/service/consys/ServiceErrors.java
@@ -42,7 +42,13 @@ public static InvalidRequestException badRequest(String msg)
     
     public static InvalidRequestException invalidPayload(String msg)
     {
-        return new InvalidRequestException(ErrorCode.BAD_PAYLOAD, msg);
+        return invalidPayload(msg, null);
+    }
+    
+    
+    public static InvalidRequestException invalidPayload(String msg, Throwable cause)
+    {
+        return new InvalidRequestException(ErrorCode.BAD_PAYLOAD, msg, cause);
     }
     
     
diff --git a/sensorhub-service-consys/src/main/java/org/sensorhub/impl/service/consys/resource/BaseResourceHandler.java b/sensorhub-service-consys/src/main/java/org/sensorhub/impl/service/consys/resource/BaseResourceHandler.java
index 93fa8048d..39e61c0aa 100644
--- a/sensorhub-service-consys/src/main/java/org/sensorhub/impl/service/consys/resource/BaseResourceHandler.java
+++ b/sensorhub-service-consys/src/main/java/org/sensorhub/impl/service/consys/resource/BaseResourceHandler.java
@@ -355,7 +355,7 @@ protected void create(final RequestContext ctx) throws IOException
         }
         catch (ResourceParseException e)
         {
-            throw ServiceErrors.invalidPayload("Invalid payload: " + e.getMessage());
+            throw ServiceErrors.invalidPayload("Invalid payload: " + e.getMessage(), e);
         }
     }
     
@@ -399,7 +399,7 @@ protected void update(final RequestContext ctx, final String id) throws IOExcept
         }
         catch (ResourceParseException e)
         {
-            throw ServiceErrors.invalidPayload("Invalid payload: " + e.getMessage());
+            throw ServiceErrors.invalidPayload("Invalid payload: " + e.getMessage(), e);
         }
         
         // update in datastore