Question on Plesk Mail

[Lady Ambrosia]

I've just gotten my mail enabled for the Plesk, and I've done everything in the Plesk User's Guide about how to set up your mailbox and all of that.  But when I try to log into my webmail, I keep getting this error:  Error connecting to IMAP server: [] .

Any ideas or help?  I'm a little confused on this one.  Thanks in advance.