You didn't give info this issue also the same with other webmail (roundcube for example).
And your info just related to Afterlogic.
And then you give info login via 587 for different product (Kloxo and Kloxo-MR as different product especially in context email because using different variant of qmail; qmail-lxcenter vs qmail-toaster).
FYI, port 587 not work for my account on lxcenter.org.
So?.
Ok, so let's just try making this usable at least on Outlook 2003.
Logging to POP3 ok,
Logging to IMAP ok,
Sending via SMTP needs testing on static IP,
Sending via SMTP on port 587 not possible - login error
Receving mails via POP3 not working - different server reports that mail is delivered successfully, but it's gone...
Port 587 is a must have, port 25 blocked is blocked in most polish ISP's due to SPAM.