243823 Lyris server troubleshooting

We have a Lyris email server and we have it set up so that administrators can have the server send an email to the list simply my sending an email to a specific address. Currently we are running into a problem where some admins cannot do that. They get an error message returned to them that says "Policy not satisfied (in reply to MAIL FROM command)". I've been going through and checking everything in the system, but am at my wits end. I need some help from someone who knows the ins and outs of Lyris server setup. Thanks!