You have reached the limit of invoices you can approve.
If this error is showing on your invoice(s), it means that the amount of invoices currently allowed to be published to Xero has been exceeded. This limit is imposed by Xero depending on the package you are signed up for. For further details on this limit, please contact Xero support directly.
As this limit is set by Xero rather than AutoEntry, there is nothing that can be done on our end to push these invoices through. For this reason, we would recommend unpublishing the affected invoice(s) for the time being, and republishing at a later time.