diff --git a/composer.json b/composer.json
index 7f74eb0..bf1d6e0 100644
--- a/composer.json
+++ b/composer.json
@@ -28,7 +28,8 @@
     "citrus-framework/configure": "^1.0",
     "citrus-framework/intersection": "^1.0",
     "citrus-framework/variables": "^1.0",
-    "citrus-framework/http": "^1.0"
+    "citrus-framework/http": "^1.0",
+    "ext-dom": "*"
   },
   "require-dev": {
     "php": "^7.3",
diff --git a/src/Sqlmap/Parser.class.php b/src/Sqlmap/Parser.class.php
index 228ad75..b4895f2 100644
--- a/src/Sqlmap/Parser.class.php
+++ b/src/Sqlmap/Parser.class.php
@@ -564,7 +564,7 @@ protected function _isDatetime(DOMElement $element): Dynamic
 
         $property = $this->callNestPropertyValue($this->parameter, $dynamic->property);
 
-        if (false !== strtotime($property))
+        if (false === is_null($property) and false !== strtotime($property))
         {
             $dynamic->query = $this->_nodes($element->childNodes);
         }