Minecraft LAN says Unknown Host when trying to connect?

My sister and I are trying to connect to a LAN world, and when either of us opens to LAN and the other tries to connect, it says unknown host. We're both on the same wifi and have never had problems with LAN before. We just added mods but we both have them and their the same version. Any solutions/ ideas? Thanks.

Read more: Minecraft LAN says Unknown Host when trying to connect?