help - Unable to establish the VPN connection between interface

Hi there,

need help please.

we run under two networks by two interface, (interface-A and interface-B).

we've set up VPN SSL to connect interface-B.

previously, user from interface-A can connect to interface-B via VPN SSL. we used firmware 5.0

as we noticed, after we upgrade to 5.2., user from interface-A can't connect to interface-B via VPN SSL.

shown error as below:

--------------------------- Warning --------------------------- Unable to establish the VPN connection. The VPN server may be unreachable. --------------------------- OK    ---------------------------

please kindly help to fix it.

thanks in advance.