Portable monitor ?

Hey everyone

I just got an Arzopa portable monitor and I have some trouble making it work. I tried plugging it directly to the Ally X with the Usb c cable : when I do that the screen turns on but says No Signal but the Ally screen is still on. When I use the Asus Plug Dock via HDMI, the Ally's screen turns off but the montior doesnt turn on. Did I do something wrong ? Or Should I return the monitor?

Thank you