Error: REFCLK port on the PLL is not properly connected on instance sys_ctrl:uut_sys_ctrl|my_pll:my_pll_inst|my_pll_0002:my_pll_inst|altera_pll:altera_pll_i|general[0].gpll. The reference clock port on the PLL should always be connected. If there is no reference clock, the PLL will not function correctly.