I have a Mikrotik RB3011 and it is configured with a L2TP IPSec VPN and when both a windows computer and a osx computer are in LAN they connect to the VPN, but when they are outside only the osx computer connects to the VPN.
I have the following ports open in the firewall:
UDP - 4500
UDP - 500
UDP - 1701
Also when the osx computer connects doesn’t matter where it always shows up in the logs but the windows computer only displays logs when on LAN.