Does it work from behind a NAT or firewall?
AICCU works from behind a NAT setup it is even capable of passing most firewalls. Do note though that AICCU is only the tool for setting up a tunnel. The tunneling protocol itself must be able to cross a NAT too. In general AYIYA will work in most situations, unless it gets firewalled.
To be able to use AICCU, one should also be able to access the TIC service.
Also see FAQ: Firewalled.