My children and I automatically got the 1.5.3 update on our Fires.  While I am using a hotspot and they are using the home guest network, I can connect to either of their games but they can't connect to each other.  When I am using the same local network as them, it hangs at "connecting to multiplayer game" for about twenty seconds, then says "Unable to connect to world".  I then tried to connect from my Samsung Galaxy phone and from my Windows 10 bedrock edition.  I get the same error.  I tried to have my children connect to me using all three devices and had a same result.  When I switched back to my hotspot they could both connect.