Hi, everything works perfectly except I receive a mail each hour like below

This email is sent by logcheck. If you wish to no-longer receive it,
you can either deinstall the logcheck package or modify its
configuration file (/etc/logcheck/logcheck.conf).

Security Events
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Dec  2 23:02:08 localhost postfix/smtpd[1167]: _sasl_plugin_load failed on sasl_auxprop_plug_init
for plugin: sql
Dec  3 00:00:02 localhost postfix/smtpd[1269]: _sasl_plugin_load failed on sasl_auxprop_plug_init
for plugin: sql

System Events
=-=-=-=-=-=-=
Dec  2 23:02:08 localhost postfix/smtpd[1167]: sql_select option missing
Dec  2 23:02:08 localhost postfix/smtpd[1167]: auxpropfunc error no mechanism available
Dec  3 00:00:02 localhost postfix/smtpd[1269]: sql_select option missing
Dec  3 00:00:02 localhost postfix/smtpd[1269]: auxpropfunc error no mechanism available