Plesk Premium Email is slow or error 504 is displayed: Connection timed out after 10000 milliseconds

Alexander Davydov

Updated August 11, 2026 16:28

Plesk for Linux kb: technical ext: kolab

Applicable to:

Plesk Premium Email interface, its emails and other menus load slowly and may fail with 504 error message.
Following error messages can be found in /var/log/roundcubemail/errors.log file:

CONFIG_TEXT: PHP Error: Curl error: Connection timed out after 10000 milliseconds in /usr/share/pear/HTTP/Request2/Adapter/Curl.php on line 149 (GET /n9HYdwfLMCi5oBXo/?_task=mail)
PHP Error: Curl error: Connection timed out after 10001 milliseconds in /usr/share/pear/HTTP/Request2/Adapter/Curl.php on line 149 (GET /n9HYdwfLMCi5oBXo/?_task=mail&_mbox=INBOX&_action=compose)

Firewall does not permit recursive connections to the global IP address.

Connect to the Plesk server via SSH
Depending on your local IP address, add one of the following rows to /etc/hosts file using any text editors like vi-editor:

CONFIG_TEXT: 127.0.0.1 webmail.example.com

CONFIG_TEXT: 10.10.10.10 webmail.example.com

Alternative solution

Connect to the server via SSH
Configure /etc/roundcubemail/kolab_files.inc.php file in the following way:

CONFIG_TEXT: $config['kolab_files_url']='https://webmail.example.com/chwala';

Additional information regarding this configuration can be found in Kolab documentation.

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