[Fix] Sharepoint: Embedding content from this website isnt allowed, but your admin can change this setting.

If you are trying to embed an external page into your SharePoint page and you get the above error, the reason for this error is that this domain is not added to the list of "Allow contributors to insert iframes only from the following domains"

Below are the steps to fix this issue, note you should be a SharePoint Admin in order to make the changes.

1. On the SharePoint page, select Settings icon on the top right.
2. Now select Site information option.
   
3. You will see a side pane, select "View all site settings".
   
4. From "Site Collection Administration" select "HTML Field Security".
   
5. Now select "Allow iframes from this domain" radio box and add the domain you want to embed.
6. Make sure to click Add and then OK to apply changes.
   

Now when you try to embed the URL with the domain, this should not cause the below error!