Quartus II Fitter error in connecting the output of IOPLL to refclk of ATX PLL

Hello,

I am creating a Quartus project to transmit high-speed data using the Arria 10 Transceiver Native PHY. I am supplying the the serial clock (at 1.5GHz) to the tx_serial_clk0 using Arria 10 Transceiver ATX PLL which generates 1.5GHz clock using input 150MHz clock. I am creating this 150Mhz clock using another PLL (Altera IOPLL) that takes the 50MHz FPGA clock as the input. I have attached the qsys design screenshot of the project.

The compilation of the design is successful. However, the fitter prompts an error which I am not able to understand. The error prompt is:

Error (11192): Input port "REF_IQCLK[0]" of "HSSI_PMA_LC_REFCLK_SELECT_MUX" cannot connect to PLD port "OUTCLK[0]" of "IOPLL" for atom "tx_phy_qsys:tx_phy_qsys_1|tx_phy_qsys_altera_iopll_171_zoxksfy:iopll_0|altera_iopll:altera_iopll_i|twentynm_iopll_ip:twentynm_pll|iopll_inst".

Extra Info (13133): Output port's "OUTCLK[0]" atom name is "tx_phy_qsys:tx_phy_qsys_1|tx_phy_qsys_altera_iopll_171_zoxksfy:iopll_0|altera_iopll:altera_iopll_i|twentynm_iopll_ip:twentynm_pll|iopll_inst".

Extra Info (13134): Input port's "REF_IQCLK[0]" atom name is "tx_phy_qsys:tx_phy_qsys_1|tx_phy_qsys_altera_xcvr_atx_pll_a10_171_7s4kdty:xcvr_atx_pll_a10_0|a10_xcvr_atx_pll:a10_xcvr_atx_pll_inst|twentynm_hssi_pma_lc_refclk_select_mux_inst".

Extra Info (12879): Input port "REF_IQCLK[0]" of "HSSI_PMA_LC_REFCLK_SELECT_MUX" can connect to:

Extra Info (12880): Port "O_REFCLK_A[0]" of "HSSI_REFCLK_DIVIDER"

It basically says that I cannot provide the output of the IOPLL to the pll_refclk0 of the ATX PLL. But, the ATX PLL needs reference clock of 150MHz. It does not make sense to me. Please help.

Thank you