Good evening everyone,
I think you need to configure your internet boxes,
to allow the connection to the Pronote client (open port 49300).
By default, it's port "49300", but it's better to ask for advice
from the IT person at your establishment.
If you want to keep it simple, try setting the security
of the box's firewall to "medium" or "low", and do the same
with the machine's firewall if it still does not work.
I think you need to configure your internet boxes,
to allow the connection to the Pronote client (open port 49300).
By default, it is port "49300", but it is better to consult
the IT technician at your establishment.