The likely reason for invoices not being marked as paid in Xero is that the connection between your Pin Payments and Xero account has been lost.
Reconnect your account with Xero
- First, click on the 'Disconnect' button in the Xero area of your Pin Payments dashboard. If you have more than one Pin Payments account, do the same in those accounts.
- In the Pin Payments account you want to use with Xero Online Invoicing, go to the Xero area of your dashboard and click the 'Connect to Xero' button.
- Follow the prompts to connect your Pin Payments account to Xero, and setup your Payment Service in Xero.
Please note: You can only have one Pin Payments account connected to a Xero account at any one time. Connecting multiple accounts will likely result in the same problem of invoicing not being marked as paid.