slapd shuts down for no reason

[GALAMBOS Daniel <dancsa@dancsa.hu>]

Hi,

We recently left the debian openldap, and compiled the 2.4.39 and
installed on our servers.

The old slapd failed multiple times a day, and now the new one too.

The log says:
Mar 15 07:06:25 ldap1 slapd[2798]: daemon: shutdown requested and initiated.
Mar 15 07:06:25 ldap1 slapd[2798]: conn=72598 op=1 DISCONNECT tag=120
err=52 text=
...
Mar 15 07:06:25 ldap1 slapd[2798]: conn=72570 op=3 DISCONNECT tag=120
err=52 text=
Mar 15 07:06:25 ldap1 slapd[2798]: conn=72583 fd=45 closed (slapd shutdown)
....
Mar 15 07:06:25 ldap1 slapd[2798]: conn=72602 fd=59 closed (slapd shutdown)
Mar 15 07:06:25 ldap1 slapd[2798]: conn=72603 fd=60 closed (slapd shutdown)
Mar 15 07:06:25 ldap1 slapd[2798]: slapd shutdown: waiting for 0
operations/tasks to finish
Mar 15 07:06:25 ldap1 slapd[2798]: slapd stopped.

I've run out of the ideas.

The configure was with the following switches: --enable-crypt
--enable-spasswd --enable-modules --enable-ppolicy --enable-syncprov
--enable-unique --with-cyrus-sasl   using libdb5.1-dev (deb 5.1.29-5)

Can you give me some pointers where to search for errors?

thanks,
Dancsa