ID:169010 Cannot place I/O pin <name> in VREF pin location <name> -- I/O standard assigned to pin requires VREF value

CAUSE: You assigned the specified I/O pin to the specified VREF pin location in the device. However, the Fitter cannot place the pin in the location because the I/O standard assigned to the pin requires a VREF value.

ACTION: Assign the I/O pin to a different location that is not a VREF pin location.