L2TP connection fails with Mac OS Ventura, but works with windows

@mMontana Sorry for the late reply.

If your firewall is behind NAT, you need to manually change the local policy to the public IP and allow IKE, NATT, and L2TP-UDP on the WAN interface. you may refer to this clip.

Moreover, regarding the username/password incorrect issue, there is a case that some users may encounter, that is, the user account reaches the max number of simultaneous login. when it reaches the limitation, it rejects and show "username/password incorrect". You may enable "user idle detection" to force the idle user to log out.