Employee unable to start journey by notification

Hi Team,

we are encountering an error when an employee tries to start a journey through the notification.
We have set up the journey notification as follows:

When the employee receives a notification about a new journey and clicks to start it, the page displays an error.

Could this issue be related to missing privileges in my custom role? If so, could you advise which duties or privileges I need to add to resolve this issue?

Thanks in advance,
Vittoria