Melissa wrote on 09/13/2010 01:33:56 PM: > I think this problem is from your enterprise SMTP servers. They're > objecting to Listserv sending too many messages in one connection. > You'll need to contact whomever runs those servers and ask them to > "whitelist" your Listserv server. I suspect it is actually too many connections per time unit (sec/min/day) from the Listserv host to the SMTP server. Connection limits are valid to throttle various forms of malware. The admin for that server would be the authoritative answer on why it happens and how to fix it. In any case, the Listserv host will need to be whitelisted or otherwise exempted from this limit. Confidentiality Notice: This electronic message and any attachments may contain confidential or privileged information, and is intended only for the individual or entity identified above as the addressee. If you are not the addressee (or the employee or agent responsible to deliver it to the addressee), or if this message has been addressed to you in error, you are hereby notified that you may not copy, forward, disclose or use any part of this message or any attachments. Please notify the sender immediately by return e-mail or telephone and delete this message from your system.