Check your SmarterMail DNS.
Google DNS, and others public DNS servers are " cumulative," racking up queries for everyone who uses them, and, after 200,000 queries are blocked.
You should be using a local DNS server.
We have NS1.CHICAGONETTECH.COM, as a local, and our secondary is off-site.
You should also disable DNS CACHING, as it is easily corrupted;
Disable the user'sability to override spam settings;
Disable the user's ability to write custom filters.
Those will all bite you, bug time, and cause all kinds of issues, which can become near impossible to troubleshoot.
Bruce Barnes
ChicagoNetTech Inc
brucecnt@comcast.net
Phonr: (773) 491-9019
Phone: (224) 444-0169
E-Mail and DNS Security Specialist
Network Security Specialist
Customer Service Portal: https://portal.chicagonettech.com
Website: https://www.ChicagoNetTech.com
Security Blog: http://networkbastion.blogspot.com/
Web and E-Mail Hosting, E-Mail Security and Consulting