Once the Dongle is connected to your computer (Dongle connexion), you can find the error codes in the 'Stream' tab, under the 'Alerts' section.
To see the steps to access the 'Alerts' section, please watch the following video.
To find out what steps to take based on the reported error codes, you can consult the following step-by-step guide:
VEFAA - Listing Codes Erreur.pdf
As a reminder, if you wish to open a support ticket, you can do so via the dedicated page: https://vefaa.odoo.com/helpdesk