diff --git a/source/java/org/alfresco/repo/web/scripts/calendar/UserCalendarEntriesGet.java b/source/java/org/alfresco/repo/web/scripts/calendar/UserCalendarEntriesGet.java
index 80c6f04983..42b4436c5a 100644
--- a/source/java/org/alfresco/repo/web/scripts/calendar/UserCalendarEntriesGet.java
+++ b/source/java/org/alfresco/repo/web/scripts/calendar/UserCalendarEntriesGet.java
@@ -25,6 +25,8 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import javax.servlet.http.HttpServletResponse;
+
 import org.alfresco.query.PagingRequest;
 import org.alfresco.query.PagingResults;
 import org.alfresco.repo.calendar.CalendarServiceImpl;
@@ -63,6 +65,13 @@ public class UserCalendarEntriesGet extends AbstractCalendarListingWebScript
       if (siteName != null)
       {
          site = siteService.getSite(siteName);
+         
+         // MNT-3053 fix, siteName was provided in request but it doesn't exists or user has no permissions to access it.
+         if (site == null)
+         {
+             status.setCode(HttpServletResponse.SC_NOT_FOUND, "Site '" + siteName + "' does not exist or user has no permissions to access it.");
+             return null;
+         }
       }
       
       return executeImpl(site, null, req, null, status, cache);
diff --git a/source/test-java/org/alfresco/repo/web/scripts/calendar/CalendarRestApiTest.java b/source/test-java/org/alfresco/repo/web/scripts/calendar/CalendarRestApiTest.java
index b82449cb6a..acfd8d8db2 100644
--- a/source/test-java/org/alfresco/repo/web/scripts/calendar/CalendarRestApiTest.java
+++ b/source/test-java/org/alfresco/repo/web/scripts/calendar/CalendarRestApiTest.java
@@ -39,6 +39,7 @@ import org.alfresco.service.cmr.security.PersonService;
 import org.alfresco.service.cmr.site.SiteInfo;
 import org.alfresco.service.cmr.site.SiteService;
 import org.alfresco.service.cmr.site.SiteVisibility;
+import org.alfresco.util.GUID;
 import org.alfresco.util.PropertyMap;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -1182,6 +1183,20 @@ public class CalendarRestApiTest extends BaseWebScriptTest
        events = result.getJSONArray("events");
        assertEquals(0, events.length());
     }
+    
+    /**
+     * Listing for a user
+     */
+    public void testMNT_3053() throws Exception
+    {
+        String siteName = null; 
+        do
+        {
+            siteName = GUID.generate();
+        }
+        while (siteService.getSite(siteName) != null);
+        sendRequest(new GetRequest("/calendar/events/" + siteName + "/user"), 404);
+    }
 
     /**
      * Repeating events support, across both the site