UCC2897A: Can't load

Using UCC2897A design a DC/DC power supply, but now the power supply can't load(just can load  about 50mA )

the arguments of the DC/DC are as below:

INPUT: 60-100VDC 

OUTPUT: 48V/10.5A

Debugging

1, DNP the TL431 CC loop

2, cancel the CT, using the resistance to detect the current in low-side MOS

Question:

1,  Any Suggestions for debugging?

2, Any suggestions for Transformer designning?  could you provide the calculation for  UCC2897A transformer design?

the sch and the transformer drawing are attached.UCC2897A sch and transformer.docx