If you've enabled the Xero integration and receive the error message below when checking out a booking, adding a refund or applying a refund, it will be because the bank account selected under Banking in your Xero integration settings is not a bank account in Xero.
Fixing the error
To fix the issue, you will need to do the following:
While in Preno, go to Settings > Integrations > Connect with Xero and click Settings.
Scroll down to Banking.
Under Default account, select a bank account from Xero. It has to be a bank account in Xero and can't be a current asset or another type of account.
If you're unsure of which bank account to select, please check out this article, "Xero integration - What bank account should I select".
Scroll up and click Save.