Error(175019): Illegal constraint of I/O pad to the location PIN_K12

Custom design using Arria 10 SOC, 10AS066KF40- The clkout pin (PLL_3H_CLKOUT0P,PLL_3H_CLKOUT0,PLL_3H_FB0/LVDS3H_15P/DQ68 ) which is also defined as LVDS in pin description, when used as LVDS differ...