Is the e-mail address correct? As an admin you can see this via Employee > Personal Information;

Is 'online access' enabled? You can check this via Employee > Modify > General data;

Did they forget their password? They can request a new one through our login screen;

Did they receive an invitation? Has the employee already logged in before? If not, send them a new invitation through Employee > modify > send invitation;

Does the employee have access to the e-mail address with which he or she is registered with us? If not, please change the e-mail address. The employee can then log in immediately with the new e-mail address.