After a fresh install I also got the same issue, not only on Afterlogic but also some of the other webmail clients. Here is how I solved Afterlogic issue:
Open the file /home/kloxo/httpd/webmail/afterlogic/data/settings/settings.xml.php and locate AdminPassword entry and set it to empty value:
<AdminPassword />
Save the file and then use your browser and log into webmail.your-domain.com/afterlogic/adminpanel with:
username: mailadm
and
password: 12345
Set a new password under System > Security tab.
In the System tab you can see the current MySQL Connection settings. You may keep the settings as is, but you need to click on update tables.
Remember to save before logging out of mailadm.
Now, in the browser you should be able to log into webmail using Afterlogic. Once you are logged in you probably also need to access settings and remove the checkmark on port 25.
Hope this helps.