You need one of these:
Shunyata - 15Amp Cable to 20Amp Component Adapter (ea) | Shop Music Direct
It should be fine if you're using the Everest only for front end. If you also have your amps connected to the Everest, then you need to have your PC reterminated with a 20A IEC (for example: FI-52 NCF | FURUTECH) or purchase a new PC to the wall with a 20A IEC.
I'd avoid if possible using this adatpter as shown above for more than a temporary measure until you find the correct 20AIEC terminated cord.
I have the item in my setup and find it loose fitting -I have to cable tie the two connections to get a firm seating) and frankly poorly made for the asking price--$225USd(?)
Go for the proper terminated cord.
B