Question "input not supported" from displayport

[kojie2u]

Tried installing a new GPU but upon startup, my monitor displays an error popup of "Input not supported," I tried plugging in my monitor and TV at the same time but only the TV was able to display properly. The only difference I can think of between my monitor and TV is that my monitor is 1600x900 resolution and 59hz refresh, while my TV is 1380x768 resolution and 60hz refresh
Using my TV's display, I've tried to lower the resolution on both displays, nothing changed on my monitor, still the same "input not supported" popup.

Something else to note: my monitor is VGA and my GPU is DVI-D, but I do have a working active adapter.

I'd be grateful to receive any help, here are my specs

My specs are:
Processor: Intel(R) Core(TM) i5-4440 CPU @ 3.10GHz 3.10 GHz
Installed memory (RAM): 12 GBs (both memory sticks are used)
GPU (current): Intel(R) HD Graphics 4600
GPU (tried installing, having problems with): Radeon RX 550 4GB GDDR5
Motherboard: 088DT1
1TB HDD
Display: acer monitor k202hql

 

[Chris_812]

Rx 550s vary on what exact display output it uses. Dvi-i and dvi-d. Chances are the one you have is not going to be compatible to vga without a converter. I believe dvi-i will work with vga.

Can you look through the specs of the exact model rx 550 you have and see what exact display ports it offers?

 

[Chris_812]

I just re read and you said you had dvi-d. From what I've read that wont work to vga with a converter of some sort. But some ex 550s do use dvi-i.