Was supposed to recieve package today

A package was sent to me from jersey and it arrived in memphis tn regional distribution center last night at 8:15 PM and It was supposed to be delivered today. On my informed delivery account it now says delivery date unknown. Just wo weeks ago it arrived in memphis around the same time and was at my post office the next day. But when I check the tracking number without signing in to my informed delivery account it says "Tracking Not Available because the tracking number is invalid." What the hell is going on? I just spoke to the shipper and they checked the tracking number on usps and it showed uo for them just fine. I dont have another way of testing this or finding out what the hell is going on.