diff --git a/lib/Service/TemplateFieldService.php b/lib/Service/TemplateFieldService.php
index 5e0aafb529..4037acf9a1 100644
--- a/lib/Service/TemplateFieldService.php
+++ b/lib/Service/TemplateFieldService.php
@@ -46,12 +46,16 @@ public function extractFields(Node|int $file): array {
 		}
 
 		try {
+			if (!$file || !$file instanceof File) {
+				throw new NotFoundException();
+			}
+
 			$localCache = $this->cacheFactory->createLocal('richdocuments_templates/');
 			$cacheName = $file->getId() . "/" . $file->getEtag();
 			$cachedResponse = $localCache->get($cacheName);
-			
+
 			if ($cachedResponse !== null) {
-				// return $cachedResponse;
+				return $cachedResponse;
 			}
 
 			if ($file->getMimeType() === 'application/pdf') {
@@ -125,6 +129,13 @@ public function fillFields(Node|int $file, array $fields = [], ?string $destinat
 			$file = $this->rootFolder->getFirstNodeById($file);
 		}
 
+		if (!$file || !$file instanceof File) {
+			$e = new NotFoundException();
+			$this->logger->error($e->getMessage());
+
+			throw $e;
+		}
+
 		if ($file->getMimeType() === 'application/pdf') {
 			$content = $this->pdfService->fillFields($file, $fields);
 			if ($destination !== null) {