The MobiOne AppSync service used by the “Send to My Phone” action is a temporary hosting and update service that Genuitec provides to MobiOne users for individual and group testing of MobiOne apps during development. Thus the URL you receive when MobiOne uploads your app to AppSync is only valid for a maximum of 5 days.
We are planning to provide an extended hosting service in the future. Until then once you have completed your app design and development then you should rehost your MobiOne app from your own personal or corporate website.