What is the behavior above? I often have a public IP address to access my RouterOS. Is this safe? Help, I am a newbie, I just learned to use RouterOS.
What device model do you have? If you don’t use L2TP intentionally for VPN access to your network, it looks like a missing or misconfigured firewall. The SOHO models come with a default configuration which doesn’t permit L2TP (nor any other) access via WAN, the high end models have no firewall rules by default.
disable l2tp server if you dont need it
/interface l2tp-server server set enabled=no