Facebook showing page not found when sharing link

For me what it worked was to access the Facebook Debugger, as Goose said. I saw that the scrape was about 12 hours ago, looks like it fetches the first time and saves it as caché or whatsoever... What it worked for me is to debug the url, then click "fetch new scrape information" after the previous information has been shown. Hope it works!

For those running across this today, you might find that you also need to verify your domain and link it to your page.

To do this you need to

1. Set up a Facebook Business Account
2. Add your page to the business account
3. Verify your domain (using DNS TXT or adding a page facebook gives you)
4. Under domains, connect your page as an asset of that domain