WEBENCH® Tools/TPS5450: +15V and-15V supply

Tool/software: WEBENCH® Design Tools

I'm generating +6.3 V and -6.3V using +/-15Vs

My +6.3V rail is working fine with TPS5450

But My -6.3V rail is not performing correctly. When I added a load the -6.3V drops to -1.9V.

Can't I use TPS5450 for negative voltages?

Thanks,

Regards,

Chamila