Ok, just going to give a brief run-down here.
Server started experiencing lag problems, with players all disconnecting at the same time, kind of ‘mini crashes’.
I attempted to restart the server, but due to lag, nothing came up on the screen saying ‘SERVER IS RESTARTING’, so I have no way of telling whether it did.
I assume it didn’t, as I disconnected and reconnected a few times, to try and get over the lag, and load chunks, but now, after disconnecting again, I cannot reconnect.
connection lost: connect
End of Stream
and now just, Logging in…
EDIT: It seems this was just an overly long restart, as the server is back up again now.