Client immediately disconnects when reconnecting an on-going game

[dinomaster606]

In our game all players join in a lobby level, after which they start the game and join the next level. This works fine, however if a player disconnects and tries to reconnect the on-going game again, they get immediately kicked out. We get the following message in our output log:

Closing connection: connection(0). Received message Mirror.SpawnMessage that required authentication, but the user has not authenticated yet.

We simply start the server with NetworkManager.StartServer and connect using NetworkManager.StartClient.