diff --git a/src/main/java/de/financer/controller/RecurringTransactionController.java b/src/main/java/de/financer/controller/RecurringTransactionController.java
index 792ea56..62feb32 100644
--- a/src/main/java/de/financer/controller/RecurringTransactionController.java
+++ b/src/main/java/de/financer/controller/RecurringTransactionController.java
@@ -45,6 +45,7 @@ public class RecurringTransactionController {
 
     @RequestMapping("createTransaction")
     public ResponseEntity createTransaction(String recurringTransactionId, Long amount) {
-        return this.recurringTransactionService.createTransaction(recurringTransactionId, Optional.of(amount)).toResponseEntity();
+        return this.recurringTransactionService.createTransaction(recurringTransactionId, Optional.ofNullable(amount))
+                                               .toResponseEntity();
     }
 }