How To Use List Expansion to Expand Distribution Lists

Applies To:   PoliteMail Desktop    PoliteMail Online   □ PoliteMail O365

Version:  4.9    5.0    5.1+

Dynamic distribution groups (DDGs, and often also called Dynamic Distribution Lists or DDLs) are Entra ID objects created to expedite the mass sending of messages in Microsoft Exchange.  PoliteMail can expand DDGs in version 4.97 and higher using Graph or EWS with OAuth.  

PoliteMail can also "fall back" to other methods if a mailing list fails to expand with the primary method. For example, if your organization uses Graph, and the list fails to expand with Graph, it will fall back to EWS on the server side for expansion. If that fails, list expansion will attempt to expand the list on the client side using Graph, then EWS, and then finally MAPI.

In PoliteMail version 5+, this setting is under 'Enabling List Expansion', whereas earlier versions refer to this as Fallback Expansion.

Enabling List Expansion / Fallback Expansion

 To enable List Expansion, go to POLITEMAIL > Account (Account Settings in version 4.9x) > Preferences.

There are 3 expansion methods - Graph, EWS, and MAPI. If your organization is not utilizing a particular method, it will appear grayed out and will not be available for selection.

Refer to this chart for list type and compatibility with the current preferred method. Group definitions can be found below.

Local Contact GroupView Membershipn/an/a
Mailbox Contact GroupView MembershipView MembershipView Membership
Security GroupView MembershipView MembershipView Membership
Universal GroupView MembershipView MembershipView Membership
Dynamic Exchange GroupCountView Membershipn/a
O365 Dynamic Groupn/an/aView Membership
O365 Groupn/aView MembershipView Membership
Distribution Groups with hidden membershipn/an/aView Membership

Contact Lists: Local to the Outlook Client, not managed by Exchange typically

Distribution Lists (DL): Static List of Membership, may contain Nested DLs

Dynamic Distribution List (DDL): Membership is generated based on a Query

Query Dynamic Distribution Lists (QDL): A DDL where the membership is pulled at send time

Visit these sites for additional information regarding Distribution Groups and EWS.

Failed Expansion

There are a number of reasons why your mailing list has failed to expand and your message hasn't been sent. Here are a few examples and their solutions:

Expanding Dynamic Distribution List with Graph and MAPI only enabled.

Suggested solutions:

  1. Configure EWS to expand your Dynamic Distribution lists
  2. Convert the Dynamic Distribution list to an Office 365 Dynamic Group

Expanding Distribution Group with members marked as hidden on exchange

Suggested Solution:  Setup and Enable Graph as an additional expansion mode