@amatur_1213 Same issue, yesterday i was playing online and my network provider had maintenance, so it kicked me out of the network and booted me back to the nfs menu, so i was playing solo mode, upgraded my evoIX and shut down the game, nest day i went straight online and i got the error code with the inventory failure.
i tried a few times rebooten etc, and ques what my whole save data was gone and was at a new game... not that i really care cause i was planning to do a whole new game again tho, but its weird it has to do something with solo mode progress (buying a car/upgrading) then going back to online i think this game uses 2 types of savedata's, 1 in your ps4 and 1 on their servers, so when progressing offline, it doesn't match the savadata on their server