On your computer:
Go to the Virtual Cards section.
Click the "Proceed with Verification" then click "Start" on the pop-up screen.
Enter your personal information as required to complete Identity Verification.
Once completed, click the Verify button to proceed with verifying your funding source.
Click the "Charge My Card To Verify" button and enter the verification amount.
After that, you should be able to create a Masked Card by clicking the '+ New' button and choosing the "Create new Masked Card" option.