If your using Horde as your preferred webmail client on a Plesk virtual hosting server, its advisable to enable (and force) the use of HTTPS in order to secure webmail users against their login information and email communication being compromised.

To force HTTPS within Horde:

vi /etc/psa-webmail/horde/horde/conf.php

Then change:

$conf['use_ssl'] = 2; 

to:

$conf['use_ssl'] = 1;

Next edit the Horde virtual host file:

vi /etc/httpd/conf.d/zzz_horde_vhost.conf

And just below the "ServerAdmin Ova e-mail adresa je zaštićena od spam robota, nije vidljiva ako ste isključili JavaScript " line add:

-> see here

Make sure to tab the lines in to match the delimiter of the previous servername/alias/admin lines.

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