My Minecraft PE won't work correctly when I join external servers?

So, yesterday I discovered that I could join external servers on MCPE. I correctly entered a server's information and the name lit up with all these different colours and had a green circle next to the Red Cross button. I'm guessing this means it's online. Anyways, I entered the server and noticed I couldn't move. I also noticed that I was in the sky, with nothing below me, and nothing else in sight except for other players who appeared to be vibrating. Regardless, I registered etc and still couldn't move or see anything but endless sky. I researched the problem and apparently it's a bug that resolves itself by closing down the app and entering/exiting the server until it works. This does not work for me. I have even waited and waited, hoping that it's just bad lag, but it won't resolve itself. My sister also has the same problem with her MCPE and we're clueless as to why it's happening. Please, could someone give us some real help on how to play on these servers without anything glitching out like this.

I have the most recent version of the game. I have reset my device. Force closed the app. I have even redownload end the app.

Added (1). The servers I'm trying to connect to are pocket edition servers so they should be working. As well as this, other players in the servers appear to not be experiencing this. So I don't think that it being PE is the problem.

The problem is the fact that you're playing Pocket Edition. Play on PC.