I can't reproduce this error on my devices. Asked friends for help and waiting for their feedback.
This is weird though. Usually, errors like these affect all players. Just to be sure, you just get into the on-map menu, tap on the items button in the top section and get this error? Or did I miss something?
Well, even if the error persists, you don't really need items menu. You can equip new stuff via the equip menu and craft materials are all listed in the lower section of the on-map menu.