diff --git a/src/Renderer/BlockSnippetRenderer.php b/src/Renderer/BlockSnippetRenderer.php
index <HASH>..<HASH> 100644
--- a/src/Renderer/BlockSnippetRenderer.php
+++ b/src/Renderer/BlockSnippetRenderer.php
@@ -56,7 +56,7 @@ abstract class BlockSnippetRenderer implements SnippetRenderer
         }
 
         if (!class_exists($blockClass)) {
-            throw new CanNotInstantiateBlockException(sprintf('Class %s does not exist.'));
+            throw new CanNotInstantiateBlockException(sprintf('Class %s does not exist.', $blockClass));
         }
 
         /** @var Block $blockInstance */
Issue #<I>: Add missing variable