That’s strange. I just tested it myself and I see no problem.
As you can see in the error message, the host dash.infinityfree.com is specifically allowed, so the URL https://dash.infinityfree.com/profile/authentication should be fine. If it didn’t then not a single form in the entire client area would work.
Do you have any browser extension that could be interfering with the page or security settings? Ad and tracking blockers notably tend to do that.