Matching error

Our client just published our first multiplayer game:
https://minipool.io

Sometimes after finishing a match I want to replay the game and I got matched against myself. Is there a way to avoid that?
using colyseus v0.9.11

Hi @Enriqueto! Nice to see you around here! Are you locking the room after the match has started?

Maybe the second player closed the connection - which freed up space for another user, you when you called to join it again, you could be matched against yourself. Is that the case?

Happy holidays!
Cheers