TFM crashes every 5-10 minutes, and it's terrible. I can't play normally. I don't know why this happens. So, I'll clarify the problem.
I'm playing. After 5-10-20 minutes, TFM crashes. I log in again, enter the password, and it says: already connected. I don't know what this is, but I haven't told anyone the password and I won't. Until I log in as a guest, I can't log in. Maybe someone knows why this is?

Does the game really crash (freeze up completely or shut down), or does it just disconnect you or become partially unresponsive - for example, it won't start a new round when the current one ends, or let you change rooms, but some things like the chat may still work?

If the program actually crashes, the problem is likely on your own system. If it only disconnects, it could be that your internet connection is unstable, or it may be related to the server problems that have occured at some times lately, which I have posted about here:
The recent server / disconnection problems

As far as I can tell, the "already connected" message usually just means that the server didn't log you out right away when you got disconnected; you should normally be able to log back into your account after a few minutes.

(I have also had this message appear on occasions when the standalone Flashplayer that I'm running the game on didn't shut down completely after closing the game - the program window disappeared, but the application kept running -, and I had to kill the process to actually disconnect from the game. I'm on Linux; not sure how likely this is to happen on other systems, or with the Steam version of TFM.)

thank you, I will be vigilant