CDN not working properly.

I have both Smush and Hummingbird CDN active but still, GTmetrix YSlow reporting about Use a Content Delivery Network (CDN). Please check and help.

https://cdn.livechat-static.com/api/file/lc/att/8801096/82984aedb6af12f5d3401609eecbc36a/WeChat%20Screenshot_20200218133950.png