If you're using BIS you'd have to make sure that your server has POP or IMAP available. If your server uses POPS or IMAPS then make sure you select SSL when you setup your BIS account. I used BIS a long time ago for an account on my Zimbra server and it worked for me using IMAPS. You'll get quicker mail delivery with BIS if you use IMAP because I believe BIS supports IMAP IDLE now.
Release 6.0.2_GA_1912.UBUNTU8_64 UBUNTU8_64 NETWORK edition + Mobile Option
Activesync with Moto Q9C, HTC Touch Pro, Palm Pro, & Palm Pre