Firewall rules , so written , are not necessary , since the default policy is accept , (could be very useful for logging/debugging purpose, but your logging is disabled) and in any case are irrelevant, since the connection seems refused by the vpn server.
It is a bit hard to help you, ….. are the roles correct (server/client) on both links? psk match ? is remote host’s pubblic ip correct ? try enabling logging and take a look about what really happen on pppX interfaces , (it looks like a ip/psk/role mismatch…)