Had a working setup, now I don't. Only 2 of my 3 displays show up. Windows does not detect the 3rd. Tried different monitors and cables, no luck. I was running Win 10 1803, but after it stopped working I upgraded to 1809 as an attempted fix. After that didn't work, I ran DDU (display driver uninstaller) and uninstalled the AMD graphics driver completely, and installed the latest one from AMD's website. Nada.
I'm assuming a Windows update cause the issue, but I cannot confirm. This happened a little while ago and I don't remember exactly when.
Core i3 2130
Asus motherboard (I don't know exactly what model, PC is located at a remote location)
Asus RX 550
Try the card in another machine and see if it works. You might have just had a port on the card die. It happens.
That was my thoughts originally. However, I actually have the exact same model on hand and swapped it out. Didn't change the issue. The HDMI port works by itself, just not when using 3 displays at once.
have you tried any other drivers? or even clean installed the one you are using. you may want to run DDU and reinstall the driver.
I haven't actually, I'll try the previous version and see if that works.
I have had similar issue with an Nvidia 750ti.
I had 3 screens suddenly one of them stopped working.
I use one adapter DVI to HDMI, one HDMI and one VGA.
If I start my computer with the TV that is connected on the HDMI port on it will only detect the HDMI and the VGA. If I start the PC with the TV off it will detect the 3 screens