Forticlient stuck at 80% error -14 vpn gateway unreachable

User is stuck at 80% and consistently gets the error -14 vpn gateway unreachable.

The laptop is a HP Elitebook with Forticlient version 6.4 and authentication is done on AD. For a test me and my colleague log in on the same laptop it works fine for us.

Both my and my colleagu are in the same AD group, whilst user is in another AD group.

Strange thing is that user has a colleague which is in user's same AD group, and that colleague can login fine on a similar HP Elitebook (only a smaller version 13").

I can find no difference in the Fortigate configuration. Any suggestions on how to troubleshoot further?

EDIT: said user can login on another type of laptop just fine