Not able to set cookies on Instagram

Question

I am making a chrome-extension and trying to set cookies onto every page I visit. The cookies are getting set on every website I have tried except Instagram.

I have confirmed that the content script is running on Instagram, but the following standard 'set cookie' function is not doing anything when the script is being run on Instagram

function setCookie(cname, cvalue, exdays) {
    const d = new Date();
    d.setTime(d.getTime() + (exdays*60*1000));
    let expires = "expires="+ d.toUTCString();
    document.cookie = cname + "=" + cvalue + ";" + expires + ";path=/";
}