Symptom
After applying the 8.3.0 update, the Credit Card Number, Expiry Date, and CVV text boxes may not display on the shopping cart checkout page in certain conditions.
Solution
Apply the 8.3.1 Maintenance Release via the Utilities > Update WHMCS page.
Workaround
To fix this, perform the following steps:
1. From the WHMCS Admin Area Dashboard, go to Configuration > System Settings > Payment Gateways.
2. Click the Manage Existing Gateways tab.
3. Use the green arrows to move a non-credit card payment gateway to the first position on the page.
For example, clicking the green arrow in the example below would move the Stripe gateway down:
This makes PayPal® Basic the first gateway in the list:
