MSP430F5659: USB disconnect and connect

Part Number:MSP430F5659

Hello,

I am working on MSP430F5659 controller base USB CDC device. My device automatically connect and disconnects. I am using TI RTOS in my device. Device is not resetting or loosing power drop, but i am seeing in my laptop device Manager , my device goes OFF and Comes back.

What could be the issue here.

I have listed my five tasks for reference

1. Watch Dog handling external WDTimer IC - Pri - 8

2. Comm Task - Pri - 5 ( To Rx/Tx to/from  PC Application - USB CDC based protocol)

3. Utility Task - Pri - 2

4. Data Manager - Pri - 2

5. Measurement Manager - Pri - 1

Thanks in advance

Nitesh