i have meraki mx84 as firewall but have some spam email coming to my email server .
how can i blocked those domain using meraki mx84
Regards
Meraki MX's don't perform email filtering.
You need another appliance/solution to do this.
You need an anti-spam email.
https://expertinsights.com/insights/the-top-email-anti-spam-filtering-solutions/
You can get some marginal relief by blocking the "SPAM" content using content filtering. This does not directly address what you have asked for though.
https://www.talosintelligence.com/categories#threatcats
"spam: Known to serve, deliver or aide in the propagation of Spam."
Based on what Cisco publishes as the definition for the spam category - what do you think it blocks then?
Web Spam not Email Spam.
It will definitely be 100% accurate, but will at least filter out a lot of noise.
You have to check it with your email solution provider, either it is on Guite or Microsoft.
They can help you surely!