[horde] Unable send event notification to attendee

[NAI WEI YEK]

Dear Steffen,

Where do i check smtp server log?
Is it create a backends.local.php then put in same location
with backends.php and the backends.local.php inside i change
'$servers['advanced'] = array(
        'debug' => '/tmp/imp_imap.log',
 ),

but after i put backends.local.php and create an event add attendee test
again but doesn't generate the log file in tmp folder.

or im doing wrong way? how can i check smtp server logs?

Thanks and best regards,
Nai Wei