A possible emergency fix is if the email needs to go out shortly is
removing the tracking links.
Could you please post the HTML source for the entire line defining that link? In alternative, we can have a Support Case if you have any concerns regarding privacy.
The link to initiate a Skype call/text is risky unless you are sure most of your audience is using Skype.
Uses who do not have Skype installed will be redireted to non-existing links (hopefully the CNAME) since the desktop can not find the application.