TPS61085: About output current

Part Number: TPS61085

Hi.

I refer to the datasheet on page 9 to design a 3.3V-12V boost circuit. 
The output is 12V before the UVC is attached. 
However, after the UVC is mounted, the output is pulled down to less than 1V.
What is the problem?

UVC maximum current 350mA, Vf=5.5V

Thanks.