when I check my mainpage with GTmetrix I got the following info regarding your plugin for “Use cookie-free domains” (see screenshot).
Is there a possibility to fix this?
Gtmetrix will report asynchronously loaded assets with that issue, when in reality they are actually faster that way. That’s why you can see some other items there as well – like google analytics.js, lazy loader images etc..
I would not recommend doing anything with that, but you can turn off the asynchronous stylesheet loader feature, it will most likely resolve that, but the real page loading time may actually get slower.