Connect with and learn from others in the QuickBooks Community.
Let's review your Chart of Accounts to check if you've already created the same credit card account.
But if you're adding it through the Transactions page, you'll have to review your list of accounts connected to the online banking first.
I'm adding a few references here for ideas in managing your account and transactions: QBO Self-Help.
Keep me posted in the comments if you have any other questions.