RJ-45 connector from the white cable faulty designs

I once bought the black (red connector) and the white 15m cable (red connector). After laying the cable (by the wall) I realized that the white wire is dead. The black working properly. Checked by measuring both ends ... everything seems to be ok.

Sometime I have the connector compares the black and the white cables and the einizige difference was an elevation of about 1 mm at the end of the contacts at the white cable (hard to explain ...) Anyway, I have simply times with a pointed object sand a little ablated plastic and lo and behold, suddenly the connection is there.

From the white cable so I can only advise! take the black! :)