When targets click on a phishing link in one of the simulated phishing emails and the following page is displayed, it means that the browser has flagged the domain as deceptive due to it being blacklisted (usually, by Google Safe Browsing, but sometimes by other domain blacklists).
The only workaround for this issue is to use another domain. You can choose a different domain by changing the domain on the phishing template editor (search for Completion Settings in this article).
We regularly monitor our domains and submit review requests to Google as they get flagged. It can take anywhere from hours to weeks for a domain to go from being blacklisted to being usable again.
You can see all our domains on the Template Domains page. If a domain is inactive on that page, we do not recommend that you use it on your phishing templates. (Note: we prevent you from being able to select inactive domains on the template editor. If you had previously set an inactive domain on a template, then we recommend changing it to one that is active.)