I am having problems connecting to a RF560 using the microsoft VPN PPTP. When the customer tries it they will timeout and get an error 800. Every once in a while it will get to the login prompt but then timeout after that.

If the PPTP client is behind some firewall / NAT, then this could be a problem. The firewall / NAT must support PPTP pass-thru in order for the PPTP client to connect.

Some ISP's also block the PPTP protocol which can prevent you from connecting.