I just cant figure out what to do w/ this VPN

I know I shouldent beg, but I sorta ran out of options.
I am working to get a VPN up. The edge on the network is a velocloud, I am not too experienced with preparing the service. I am more of a Meraki / sonicwall kind of guy.
Anyways, long story short, My boss told me to get this working, and I am stumped.
Regardless of what I do, the client will not connect to the server via windows VPN. I just get a GRE error.
The server is receiving the connections (nat tells us we have incoming connections), but I never get any outbound connections.
At this point neither server, edge , personal computer, personal router have their firewalls enabled.
I just want to ask for some help, someone who understands what is going on here.
Thank you in advanced.