Session invalid or expired roundcube
1. Log in to the server
2. Access the following file
/usr/local/cpanel/base/3rdparty/roundcube/config/main.inc.php
3. Comment the line
$rcmail_config['session_lifetime'] = 10;
( It is not recommended because session timeout is a security feature. You can also try increase the default value – 10 to a higher value. )
4. Save the file.
Please do let us know if you need any further help.