If you want to reject all the Smart Matches from a specific source tree in one go, this is how to proceed:
1. Log in to your family site.
2. Move your mouse cursor over the ‘Discoveries’ tab and select ‘Matches by source’:
You will be able to see all the matches found from a specific source in your family tree.
3. Click on the ‘Smart Matches’ tab to filter the list by Smart Matches only.
4. Click on ‘Review X matches’ to see the list of all the matches found from this specific source.
5. To reject 'all matches' at once, click on 'More actions' on the upper right hand side of the list and choose 'Reject all X matches':
This will reject all the matches from the specific source you selected and the system will remember not to suggest you these matches in the future.