Which process sends SIGKILL and terminates all SSH connections on/to my Namecheap Server?

Question

I've been trying to troubleshoot this problem for some days now. A couple of minutes after starting an SSH connection to my Namecheap server (on Mac/windows/cPanel's "Terminal"), it crashes and give the following error message :

Error: The connection to the server ended in failure at {TIME} PM. (SIGKILL)

and :

Exit Code: 137

I've tried to create some kind of log file for any SIGKILL signal, but, it seems like none can be made on a Namecheap server :

• auditctl doesn't exist,
• We can't get systemtap because no package managers are available.

Precision :

• uname -a : Linux [-n] 2.6.32-954.3.5.lve1.4.78.el6.x86_64 #1 SMP Thu Mar 26 08:20:27 EDT 2020 x86_64 x86_64 x86_64 GNU/Linux
• I calculated the time between each crash : around 6min.

I don't have a very good knowledge of Linux servers, and maybe didn't include needed information. So please ask for any specificities!