diff --git a/src/get-app-authentication.ts b/src/get-app-authentication.ts
index 519ae318..f5e15945 100644
--- a/src/get-app-authentication.ts
+++ b/src/get-app-authentication.ts
@@ -7,7 +7,7 @@ export async function getAppAuthentication({
   privateKey,
   timeDifference,
 }: State & {
-  timeDifference?: number;
+  timeDifference?: number | undefined;
 }): Promise<AppAuthentication> {
   try {
     const appAuthentication = timeDifference