If you get the 'An authentication error has occurred' message, then you need to re-link your google account to Lynkos.
To do so, follow these steps:
1- Enter this link https://myaccount.google.com/security#connectedapps
2- Click on Management of sites linked to your account
3- Click on Manage apps
4- Click Remove
5- Go back to Lynkos and enter with your Google account