Increase Roundcube Attachment Size on Plesk

Edit php.ini used by roundcube

vi /etc/psa-webmail/roundcube/php.ini

Add

upload_max_filesize = 512M
post_max_size = 512M
memory_limit = 512M

Edit roundcube config file

vi /usr/share/psa-roundcube/config/config.inc.php

Add

$config['upload_max_filesize'] = 519168000;
$config['max_message_size'] = '665M';

It seems this value is 75% of $config[‘max_message_size’]

Create custom roundcube config

mkdir -p /usr/local/psa/admin/conf/templates/custom/webmail
cp /usr/local/psa/admin/conf/templates/default/webmail/roundcube.php /usr/local/psa/admin/conf/templates/custom/webmail/

edit the file

vi /usr/local/psa/admin/conf/templates/custom/webmail/roundcube.php

Update value of FcgidMaxRequestLen to 519168000

500MB = 500 * 1024 * 1014 = 519168000

If you use Nginx Proxy

cp /usr/local/psa/admin/conf/templates/default/webmail/nginxWebmailPartial.php /usr/local/psa/admin/conf/templates/custom/webmail/
vi /usr/local/psa/admin/conf/templates/custom/webmail/nginxWebmailPartial.php

Set value of client_max_body_size to something higher

client_max_body_size 1000m;

Run

/usr/local/psa/admin/bin/httpdmng --reconfigure-all

Increase attachement size in postfix

postconf -e "message_size_limit = 524288000"

You can also change this in Plesk Admin > Tools & Settings > Mail > Mail Server Settings

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