I have worked through the various guides, and had an extensive search online too, to no avail.
I have an LG UM68P monitor, with Displayport enabled in OSD. This happened previously when I got the monitor and had my old card, an R390. Then it suddenly started working; no idea why.
I got a new card last week (RX 580), have installed the latest drivers, 17.6.1, have reset the monitor, unplugged the cables, tried both DP sockets on the card.... Am out of ideas. Is this a bug?
Please help if you can.