Id be looking at the cable, especially if you went with a budget minded cable.
Other thoughts double check your monitor imput select. Some have a DP other setting.
Also watch out if this is a 4K monitor. Thats pushing it for your hardware. Its meant to drive the laptop display at those rates, not a 34 inch behemoth!
“Two things are infinite: the universe and human stupidity, I'm not sure about the former” ~ Albert Einstein