From the warning page, you can choose to report this site as a safe site. Tap or click More information, and then tap or click the Report that this site does not contain threats link to go to the Microsoft feedback site, and follow the instructions.
If you visit a site that you think
SmartScreen should warn you about in the future, you can report it to
Microsoft by tapping or clicking the
Tools 
button, pointing to
Safety, and then choosing
Report unsafe website.