Teleport Command not working following Minecraft update?

I have no idea why this is happening, but after the Command update that Minecraft has had, all of my command blocks have basically been nullified on my server, and I can't make them work as how everyone says.

For example, I have a lobby that has a room that you push a button. The nearest player will be teleported to the next room and bang, that's how it supposed to work.

tp @p 244 9 50

That is what it's been for most of its existence, and it worked. But now, for some reason; as well on many of my other command blocks, it think that the first code is a player, and therefore doesn't read it.

[17:21:59] Error: Player not found.

So I've tried many different ways to fix this; none of which have successfully worked. I've put them in square brackets and such, and still nothing has worked! Someone please help me.

Other things I recall trying.

tp @p 244,9,50
tp @p [x=244,y=9,z=50]
tp target[@p] location[x=244,y=9,z=50]
tp @p <244 9 50>
tp @p[x=223,y=8,z=501] [x=244,y=9,z=50]