[Samba] Samba 4.2.3 sudden crash problem

[Daniele Manfredi]

Hi,
I run Samba 4.2.3 on a fileserver since 2015 without any problem even if 
in the log file I read "NTLMSSP NTLM2 packet check failed due to invalid 
signature" several times a day.
In my network are presents windows 7, 10, and some old XP machine.

Yesterday evening, for the very first time, my server chrashes and I 
have to restart it. The samba error reported is:

internal error: signal 11 in PID 1280 (4.2.3) - Please read the 
trouble-shooting section of the samba how to.

I have changed nothing in the configuration files ....

What can it happened?

Thanks in advance

Daniele