Not found by Configtool

I fabricated my own pcb board with W7100A, base on the reference design of WIZ107SR-TTL. When i power up the board, and connect it to the PC through the RJ-45 cable, the green LED on the connector is light up, and yellow LED is blinking when i try to search it through the Configtool. However, the Configtool is not able to detect the device. Please advise.