When I use the FS*4 mode of the AD9689, the PLL cannot be locked. The PLL can be locked when using other modes

When I use the FS*4 mode of the AD9689, the PLL cannot be locked. The PLL can be locked when using other modes. Using the chip AD9689BBPZ-2000, the sampling rate is 1.25Gsps, the transceiver rate is 5Gbps, and the reference clock is 250M. The FS*4 mode configuration is as follows:
Ad9689_write(0,0x81);
Wait 5~10ms;
Ad9689_write(0x120,0x02);
Ad9689_write(0x571,0x15);
Ad9689_write(0x56E,0x10);
Ad9689_write(0x570,0xFE);
Ad9689_write(0x58B,0x07);
Ad9689_write(0x58C,0x01);
Ad9689_write(0x58F, 0x0F);
Ad9689_write(0x590,0x2F);
Ad9689_write(0x571,0x14);
Wait 5~10ms;
Ad9689_read(0x56F,0x14); // PLL can't lock all the time
Ad9689_write(0x1228,0x4F);
Ad9689_write(0x1228,0x0F);
Ad9689_write(0x1222,0x00);
Ad9689_write(0x1222,0x04);
Ad9689_write(0x1222,0x00);
Ad9689_write(0x1262,0x08);
Ad9689_write(0x1262,0x00);