When you want to add custom tracking domain and your domain provider is Cloudflare, please follow the steps below:
Log in to your Cloudflare account using this link
Click “Select Website” in the navigation bar
Select the domain and click the “DNS” tab
Click on Add record
Enter the following details
Type: CNAME
Name: inst
Content/Data: prox.itrackly.com
Make sure the CNAME entry in Cloudflare is in 'DNS-only' mode (the cloud icon should be gray and not orange)
In Instantly, under Account Settings, add the new CNAME -
inst.yoursendingdomain.comwith yoursendingdomain.com being the domain you added the CNAME record under
Click on 'Check Status'. If everything is set up correctly, you will receive the following notifications below the Check Status button: CNAME Verified, SSL Verified
Go ahead and save changes