You can try the following steps. First, in root SSH, run these commands:
	
	
	
		
Please replace domain.com with the domain name. Do not replace the "" part as that's required, only the domain.com part with the right domain name.
In WHM > Exim Configuration Editor > Advanced Editor, put the following in the topmost box:
	
	
	
		
Locate the "ROUTERS CONFIGURATION" section, and right below these lines:
Put the following lines:
	
	
	
		
					
					
	
		
	
					
					
					
		Code:
	
	touch /etc/blockeddomains
echo "domain.com" >> /etc/blockeddomains
	Please replace domain.com with the domain name. Do not replace the "" part as that's required, only the domain.com part with the right domain name.
In WHM > Exim Configuration Editor > Advanced Editor, put the following in the topmost box:
		Code:
	
	domainlist blocked_domains = lsearch;/etc/blockeddomains
	Locate the "ROUTERS CONFIGURATION" section, and right below these lines:
Put the following lines:
		Code:
	
	reject_domains:
driver = redirect
# RBL Blacklist incoming hosts
domains = blocked_domains
allow_fail
data = :fail: Connection rejected: SPAM source $domain is manually blacklisted.