Hi @PwP, and welcome to the community! 

If you have previously been able to take payments with our card reader, i.e. your account is activated, then it may be the case that you don't have manual card entry activated as a payment type. You can check this easily from your Square app:

1. Select the menu icon in the navigation bar

2. Tap Settings > Payment Types.

3. Tap the toggle button on the right of the Payment Type to add or remove it from your checkout screen. Ensure that Manual Card Entry is toggled on.

4. Use the Preview button at the top of the screen to preview your new checkout screen.

Let me know how you get on!