diff --git a/server/src/index.ts b/server/src/index.ts
index f47bcdc..581dabb 100644
--- a/server/src/index.ts
+++ b/server/src/index.ts
@@ -58,7 +58,7 @@ const parseToken = (req: any) => {
  * @returns index dne v týdnu
  */
 const parseValidateFutureDayIndex = (req: any) => {
-    if (!req.body.dayIndex) {
+    if (req.body.dayIndex == null) {
         throw Error(`Nebyl předán index dne v týdnu.`);
     }
     const todayDayIndex = getDayOfWeekIndex(getToday());