Hello you can also Google nat types. Mine was cause from my router and cable modem having separate wifi's. The three different NAT types are Open, Moderate, and Strict. Your NAT type is typically the result of the network you are using to connect to the Internet, and influenced by the settings or features of the router or gateway on that network. Users with Open NAT types can generally connect with anyone, and users with Moderate NAT types can connect to users with Open or Moderate NAT types.