You'd have to provide more details if you want some help… (potential stacktrace, more detailed information on your setup, what you expect and what's happening).
Please also note that development has stopped on Portal 2.6 so even if an issue is identified the chances of it being solved are next to zero (unless you have a support contract with us). May I ask why you are still using Portal 2.6.8 instead of GateIn 3.0?