Power supply doesn't fit in we easy drive 8 gb?

My parents got me an 8 tb easy drive for backups and I just got around to setting it up tonight, but the power supply doesn’t fit! Anyone else have this problem?

what doesn’t fit ?

the 3-pole connector that plugs into the hard drive or … the power plug that goes into the mains power socket on the wall ? (which you should have got the correct plug for your country/region)

also, is it the correct adaptor ? what’s the volts / amps / watts say on the adaptor ?

Just left the house, but I believe the output is 12v at 2000ma. Every replacement supply I can find for that model has the exact same model number, input and output, and the part that shows the polarity of the part that goes into the hard drive. The wall socket is correct, it is a us plug.