Req Blacklist for certain domain @temporarymail.***

I’m testing Knews on my website, really great plugin!

Now I have a question: some subscribers subscribes using temporary email service and so do create fake email subscirbed.

How can I put this emails addresses or domains in a blacklist in order to avoid subscriptions?

For example https://10minutemail.com

Tanks,
Matteo.

https://www.ads-software.com/extend/plugins/knews/