Create Texture by Adding a Subtle Pattern as a Background Image. It's a bug?

Tell us what’s happening:
I don’t understanding why it’s wrong. Can you explain please?

Your code so far

  body {
    background: url(;

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36.

Link to the challenge:

put the link inside double quotes like

The challenge test is being a bit picky. But if you surround the link with either double quotes " or single quotes ', it should pass the tests.