What happens if a payment is erroneously rejected by the validation functionality?

After validation, you will receive a message, generated by the system, indicating that the payment could not be carried out. The message can be printed or downloaded at any time and is stored in your Rejected fee payment history, which can be found by going to Fees in the main navigation bar. This enables both you and the EPO to retrace the issue. If it turns out that a payment has indeed been erroneously rejected, the date of the attempted payment will be accepted as the payment date and any loss of rights which might have occurred as a result of the rejection will be remedied. 

Please note that rejected fees are only displayed in the Rejected fee payment history if you continue the checkout after validation. If you stop the process after validation the rejected fees will not appear in the history.