is the Primary manager using a Proxy? If it is, have you configured the proxy settings?
If you are not using a proxy or proxy settings are correct, then have a look at this KB article that explains how to disable the messages from McAfee on the database:
When you connect to the database, check if the IUS_MESSAGE_DOWNLOAD is enabled with this command:
mysql> select isactive from iv_schedulers where type='ius_message_download';
This should return true. If it is false, then you can activate the messages pull with this other command:
mysql> update iv_schedulers set isactive='TRUE' where type='ius_message_download';
Hope this helps.