I want to ensure that you can successfully process payments in QuickBooks. I will provide you with potential reasons why the payments may have been declined.

Before anything else, have you seen any error messages? If so, sharing the exact message with me would be very helpful. This information will allow us to pinpoint the issue and offer you precise solutions.

Usually, payments are declined due to the following reasons:

• Invalid account number
• Expired credit card
• Over-limit or past due
• The processor denied providing any other information.
• The issuing bank will not electronically authorize the credit card.
• The billing address in QuickBooks Online does not match the address on your statement.

Here are some tips and steps you can take to resolve the issue:

• Ensure the credit card number and verification code (usually on the back of the card) are correct. Most credit card numbers are 16 digits long. American Express cards are 15 digits long.
• In addition to the credit card number, you need to enter a verification code. Most cards, such as Visa, Mastercard, and Discover cards, have a 3-digit code on the back. For American Express, it's the 4-digit code on the front of the card.
• Ensure there are no special characters or spaces in the credit card number or other data fields.
• Use the customer's address from the US USPS website.

For additional instructions, read the details from this link: Fix customers declined credit card payments.

If none of these solutions resolve the issue, please contact your bank. They can provide insights into any reasons for the payment decline or inform you about any alerts or notifications related to the declined payments.

Additionally, I've provided these articles for your reference to offer you solutions for declined payments or failed bank transfers: Declined Payments.

Is there anything more I can help you with regarding declined payments, or do you have any other questions about QBO? You can contact to us anytime for more assistance. Stay safe!