Display Port, which one to choose or how to solve the problem?

Question

Iron

Hello, the essence of the question is this, I have a Dell U2717D monitor, or rather two monitors.
Radeon R7 250 video card.
Windows 10 operating system.
The video card has a DP port, the monitor has an MST mode, in general, this is such a thing that allows you to connect several monitors through one Display Port.
I connect DP to the first monitor, and from it the output to the second one, turn on MST and there are two monitors in the system.
I sit, work, and one of the screens often flashes, as if I was pulling out a port from it and inserting it, while not the second one, which is connected to the first one, but the first one is flashing.
I googled a little, they advise another cord, well, I bought another one yesterday, it does not help.
Maybe my vidyakha does not pull this, or maybe some kind of especially high-speed DP cable is needed for MST?
Although the vidyakha should pull, I do the same, only one of the monitors via HDMI does not blink even then.

Answer 1

I will answer those who may encounter this - on DELL monitors there is a marriage in the work of MST, and the manufacturer's warranty is often as much as 3 years, just call Dell support and in a couple of days the courier will bring you a new one and pick up the old one.

Answer 2

try to change monitors (master\slave) and enable MST on the second one too.