Well this one is strange I would have expected the Avast Web Shield to be detecting this.
However it seems to be the Avast Online Security & Privacy browser Add-on, which unfortunately doesn't give the URL of the site so it can be investigated against other site inspection tools.
What is the URL of the website you are trying to visit, ensure the link isn't active, no https or www, etc. before the domain name, e.g forum.avast.com (which isn't active/clickable).