Once a link has been rewritten with the prefix, the tooltip in the Outlook app and webmail will still show the original URL as shown below but the actual link will have the prefix
If you clicked on a link to a website that has been identified as malicious website, you may see on of the following images depending on the classifications
If very certain this was a false positive, click on Continue anyway to proceed with the website. You may open a helpdesk ticket to have that website bypass the Safe Link protection.
If it was a malicious website, you can also
report the email using the reporting add-in

Safe Link also protect links in some Microsoft Office Apps that you have signed in with your Givelify account