This happens when the temp space gets dropped for the delivery may be by the database cleanup job . I will recommend that you can rerun the workflow and this issue will get Auto resolved.
Hi , Will the below link work to generate Mobile SDK for hybrid environment ? https://experienceleague.adobe.com/docs/campaign-classic-learn/tutorials/sending-messages/push-channel/configure-push-using-aep-mobile-sdk.html?lang=en#sending-messages