VPN and Firewall

Hello

I have a client that is currently home to a 60C provides Fortigate by us, but I can not configure VPN in order to access a VLAN.

I followed the tutorial provided by Fortinet but nothing I have every time on my Mac or Windows PC an error telling me that the pre shared key is invalid.

I have yet many retyped several times but none works.

Would you have any idea where my problem may come?

Thanks, Jo'