Why is webpagetest.org showing an no max-age or expire alert for the domain?

Web Performance Discuss Test Results
1

Hi,

Here’s the link

[url=https://www.webpagetest.org/performance_optimization.php?test=170830_JC_df4ba10fbe13ce0144ddabba91ea4e59&run=2#cache_static_content]WebPageTest Test - WebPageTest Optimization Check Results

[quote]FAILED - (No max-age or expires) - https://res.ebdcdn.com/static/images/buttons/facebook-login-large.1472466057.png
FAILED - (No max-age or expires) - https://res.ebdcdn.com/upload/banner/201707/140030219842.400x400.jpg
FAILED - (No max-age or expires) - https://res.ebdcdn.com/upload/banner/201707/140124209927.400x400.jpg[/quote]

Current rules:

[code] location /static/ {
expires 1d;
alias /sites/www.eyebuydirect.com/static;
}

location /upload/ {
    alias /sites/res.ebdcdn.com/upload/;
     expires 1d;
}[/code]

When I check the link(https://res.ebdcdn.com/static/images/buttons/facebook-login-large.1472466057.png) with Google Chrome, I see it show: Cache-Control: max-age = 86400.

Colud you tell me what is your check rule? Why I am failing?