Not recognizing DX callsigns

I’m hooked into QRZ and there’s no problem with US calls, but it doesn’t recognize DX callsigns. I haven’t tried Canada.

Canadian stations are recognized.

I’m limited to what QRZ provides or whatever lookup service you have set up in your profile. Are you saying that you have entered a DX call before, and know that it exists on QRZ and it’s still not pulling it up?