Compared to any other cards you have used, your Credit One Bank card will be completely unique. The Credit One Bank advises you to only activate it using your phone by calling 1-877-825-3242, which is a toll-free number. And the cause of this is the likelihood that your privacy details will be compromised when you complete the activation process online.
Call the number on your card's sticker or possibly printed someplace on the paperwork where you received your card to activate your Credit One Bank card.
Source:
https://www.accountiod.com/credit-one-activate-card/