Make sure that your account is Active, and verify its status via your merchant account to accept payment, Tristan.
Here's how:
- Navigate to the Gear icon, then select Account and Settings.
- Select the Payments tab.
- From the Merchant details section, click the Manage account.
- Click the Account dropdown arrow and choose Account Profile.
- From the Bank Account section, see the status of your account.

If your account isn't active, we recommend contacting our Payments Live Support Team. They can check the issue and explain why you're experiencing it.
On the other hand, you can check this article and learn how to help your customers if they can't pay for an invoice: Fix payment errors for customers paying invoices online.
Also, you can view and get answers to common questions about how QuickBooks Payments deposits work in QuickBooks Online.
Lastly, if you prefer to manually log your customer's payment in the future, refer to this guide: Record invoice payments.
If you have more questions about invoice links or QuickBooks payment procedures, feel free to revisit this thread anytime.