Pokemon in Pixelmon server don't appear when I send them out?

I have a Pixelmon server for my friend and I to play on. It's been working fine for the last week, but when I came on it today, and I threw out my Pokemon it wouldn't show up. It would say "Sent out Charizard", but nothing happened. How do I make my Pokemon appear? Any help would be appreciated.

I play on Mac, and I run the server. The server has 3 GB of RAM.

Sometimes it is just lag, if it is serious lag, re-log onto your game, or maybe even restart the computer.

This sometimes happens to me. For me, if you throw it too close to you it won't appear. So try throwing it farther.