site is visible, but when sharing in facebook, under construction

Hi,

I used your plugin when building website. Now when it is visible and I try to share the website url https://www.nelkytplusblogit.fi in facebook, appear ” website is under construction”

Do you have any advice to how to fix that. I have new site and need to fix that soon.

https://www.ads-software.com/plugins/maintenance/