Failed to connect to Kali Linux remotely?

I bought a Raspi 3b + and installed Kali linux on it. Now I wanted to establish an ssh remote connection to my laptop. Also works, but unfortunately this connection lubricates every 3-4 hours and can't be restored. The Raspi is still on (the lamp is on). Sometimes I just start up the Raspi, have access to the Raspi for a few seconds and then I'm straight out, which annoys me a lot because I have to disconnect the power each time (pull the plug) and every time I'm afraid I have problems with turning off the power to get.

It's best to have a look at the log file of the SSH server. Perhaps there's already the crucial hint. What is your connection to your Raspi 3b +?
Laptop over Wi-Fi and then again over Wi-Fi to the Raspbi? For a ping from your laptop on the Raspi with the option -t, and see if something happens over time.

Can you explain this to me in more detail because I e.g. Don't know how to access the said log files (I don't know where the file is located)

Have a look at /var/log/auth.log and / var / log / syslog if you can find something there.
But please try the other things.

Thank you