Messages sent to distribution groups do not have a signature applied

Scenario

When you email to a group (either from the To: or Cc: fields), your (that is, the sender's) email signature is not added to the email received by the different recipients. Also, the return-path header of the received message is blank and only contains anchor tags.

Reason

This issue occurs when there is no sender specified in the message envelope. If the sender is blank, Signatures for Office 365 cannot identify the tenant to append for the email signature.

Resolution

• If an on-premise Active Directory exists and the distribution group is synchronized to Office 365, then: 
  
  From the distribution group Properties, set the attribute ReportToOriginator to TRUE.
  
  These changes will not take effect until the on-premises Active Directory domain has been synchronized and replicated in Office 365.
  
  
  Note: For more information, see External recipients don't receive email messages that are sent to a distribution group in Exchange Online, and senders don't receive nondelivery reports.
• If no on-premise Active Directory exists, then amend the distribution group properties in Office 365, using the Windows Powershell.
   
  You will need to:
  
  Install the Exchange Online PowerShell module
  
  Connect to Exchange Online
  
  Amend distribution group properties
  
  To complete the steps described below, you will need:
  Office 365 Global Administrator credentials

  
  To Install the Exchange Online PowerShell V2 module: 

1. Open the Windows PowerShell and run this command as an Administrator:
   
   

   Install-Module -Name ExchangeOnlineManagement

2. Confirm that you want to install this PowerShell module.
   
   

   Note: For additional installation options, see ExchangeOnlineManagement.

   
   To connect to Exchange Online: 

• If you have Multi-Factor Authentication enabled, run this command:
   

  Connect-ExchangeOnline -UserPrincipalName <UPN> -ShowProgress $true

  In <UPN> enter your username.
  
  
• If you don't have Multi-Factor Authentication enabled, run this command:
   

  Connect-ExchangeOnline -Credential $UserCredential -ShowProgress $true

  
  When prompted, enter your password (and the Multi-Factor Authentication verification code if required).
  
  

  To amend the distribution group properties:

1. Run the following command:
   
   
   Get-DistributionGroup <Group Email Address> | fl *ReportToOriginatorEnabled*
2. If the value returned is False then run this command to change it to True: 
   
   
   Set-DistributionGroup <Group Email Address> -ReportToOriginatorEnabled $true