If I turn on DP 1.2 in the monitor, my computer shows DisplayPort signal error and stop output any signal to the monitor. This situration also occurs in BIOS.

I have tried 2 display cards which support DP 1.2 (MST) (Intel HD 4600, AMD FirePro W4100). Both of them have same problem.

UP2414Q is connected as secondary monitor of my computer using mDP to mDP cable.

UP2414Q is M1T102 (A01). ISP UART ver. is 0211.

Are there any way to enable DP1.2 without error?