This may occur when La Banque Postale's ‘Certicode Plus’ is disabled. This can happen if you have recently changed devices, uninstalled the La Banque Postale app, or made changes to your Certicode Plus.
To resolve this issue, please follow these steps in order:
Open the La Banque Postale app and turn off Certicode Plus if it is not yet turned off.
Uninstall the Wero app from your device.
Open the La Banque Postale app and turn on Certicode Plus.
Install the Wero app, open it and add your bank account. You should now be able to make a payment.