Offline multiplayer isn't working

I tried playing multiplayer with my little brother we didn't have internet so I thought let's connect two phones to one hotspot and play via lan , before I started I searched if it could work ,the internet said yes but we tried playing the worlds weren’t showing on our phone ,I couldn't see his world he couldn't see my world.were both on the same Minecraft version what could be the problem,both phones were signed in before we ran out of internet