Why can't I log in with Roundcube?

Question

linux

Hello!
Trying to set up Roundcube 1.2.2.
If the server (default_host parameter) and the port for connecting via IMAP (default_port parameter) are not explicitly specified in the /config/config.inc.php file, then authorization works, and it is enough for me to specify only the server address, without the port, and I can receive / send emails. But this is not very convenient, because I need to manually enter the server address.
And if you specify these parameters, then I get an error Failed to connect to the IMAP server

Answer 1

Problem solved. In the /config/config.inc.php file I wrote:
$config['default_host'] = '%n';