Has it not been flown for a good while?
It is probably saying not able to get location due to no GPS though that is a generic DJI code not specific to P4 - does it appear to be acquiring any satellites. 
Phantom 4 is not that old but might need updating, app and firmware in controller/drone/battery.
If things need updating would not be surprised if it isn't able to lock on, as satellite lists are something they regularly update.