Are all TAN posts coming from one agent? This occurs on members' computers rather the Top Agent Network system.
Your email program has saved mailer@topagentnetwork.app your contacts/address book as the email address for that member.
However, mailer@topagentnetwork.app is the email address all Top Agent Network posts come from, so from that point onward your email program tells you that all TAN posts are coming from that one agent.
You should be able to correct it by going into the contacts/address book of your email program (or webmail account), and changing the name that mailer@topagentnetwork.app is under to Top Agent Network.
Please contact us help@topagentnetwork.com if the issue persists.