4k monitor connecting to macbook pro can only get 2560 resolution
The macbook is MacBook Pro Retina, 13-inch, Late 2013. I am connecting to Dell P2715Q with mDP to DP cable.
It was working yesterday (display at 4k resolution), but today it suddenly doesn't work, can only display 2560x1440 at max, even clicking the scale with option, the max option is still 2560x1440.
Try restarting macbook and monitor. It doesn't work.
Is this due to some recent update, or something else might be wrong.
MacBook Pro 13″, macOS 10.15