You may have encountered a situation where you\u2019ve created a Distribution List in Exchange Server 2007 and the members of the Distribution List are not receiving the messages. The postmaster account gets the following delivery error:<\/p>\n
Delivery has failed to these recipients or distribution lists: At the beginning of the detailed diagnostic message it states \u201c#550 5.7.1 RESOLVER.RST.AuthRequired; authentication required ##.\u201d<\/p>\n Here’s what may be the cause of the problem. By default, when you create a Distribution List, the delivery is restricted to users that are authenticated. When you use the Distribution List inside your organization it works fine because the users are authenticate but users outside your organization may not be able to communicate with the Distribution List members.<\/p>\n Here\u2019s what you can do to fix the problem. There is no need to restart the computer or any of the services.<\/p>\n","protected":false},"excerpt":{"rendered":" You may have encountered a situation where you\u2019ve created a Distribution List in Exchange Server 2007 and the members of the Distribution List are not receiving the messages. The postmaster account gets the following delivery error: Delivery has failed to these recipients or distribution lists: DL_name@company.com Your message wasn’t delivered because of security policies. Microsoft […]<\/p>\n","protected":false},"author":7,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[3,11],"tags":[],"class_list":["post-471","post","type-post","status-publish","format-standard","hentry","category-exchange-outlook","category-tips-tricks"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t
\nDL_name@company.com
\nYour message wasn’t delivered because of security policies. Microsoft Exchange will not try to redeliver this message for you. Please provide the following diagnostic text to your system administrator.
\n<\/em><\/p>\n
\n1.\u00a0\u00a0\u00a0 Go to the Distribution List\u2019s Properties.
\n2.\u00a0\u00a0\u00a0 Click on the Mail Flow Settings tab.
\n3.\u00a0\u00a0\u00a0 Double-click Message Delivery Restrictions.
\n4.\u00a0\u00a0\u00a0 Uncheck the box \u201cRequire that all senders are authenticated.\u201d<\/p>\n