diff --git a/module/Core/src/Validation/ShortUrlMetaInputFilter.php b/module/Core/src/Validation/ShortUrlMetaInputFilter.php
index 604f2648..6237daf7 100644
--- a/module/Core/src/Validation/ShortUrlMetaInputFilter.php
+++ b/module/Core/src/Validation/ShortUrlMetaInputFilter.php
@@ -44,7 +44,7 @@ class ShortUrlMetaInputFilter extends InputFilter
         //       empty, is by using the deprecated setContinueIfEmpty
         $customSlug = $this->createInput(self::CUSTOM_SLUG, false)->setContinueIfEmpty(true);
         $customSlug->getFilterChain()->attach(new Validation\SluggerFilter());
-        $customSlug->getValidatorChain()->attach(new Validator\NotEmpty());
+        $customSlug->getValidatorChain()->attach(new Validator\NotEmpty(Validator\NotEmpty::STRING));
         $this->add($customSlug);
 
         $this->add($this->createPositiveNumberInput(self::MAX_VISITS));