When a signature is appended by Exclaimer Cloud, in some scenarios the recipient receives the email in plain text format. As a result, the signature is also displayed in plain text format rather than HTML.
The issue occurs because the message format has been changed from HTML to plain text during delivery of the message - after it has been processed by Exclaimer Cloud. This might happen for a number of reasons, but most commonly:
- If Remote Domainconfiguration settings specified on the Microsoft Exchange server are incorrectly configured. For a solution to this issue, please click here.
- If the TNEFEnabled property is set to True, emails sent to providers who do not support TNEF (for example Gmail) will be displayed in plain text. The email will also be displayed in plain text if the recipient's email client does not support TNEF. For a solution to this issue, please click here.
To check & configure remote configuration settings
Stage 1: connect to Office 365
- Run PowerShell (as an administrator).
- Run the following command and enter Office 365 Administrator credentials:
$UserCredential = Get-Credential
- Connect to Office 365:
$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $UserCredential -Authentication Basic -AllowRedirection
- Run the following command:
Stage 2: check remote domain settings
- On the Microsoft Exchange server, launch the Exchange Management Shell (EMS).
- To view the current Remote Domainconfiguration, run the following command:
Get-RemoteDomain | fl
If the ContentType property is specified as MimeText, this is likely to be the cause of the message format being converted. The ContentType property should be configured as either MimeHtmlText or MimeHtml, where:
- MimeHtml enforces HTML format.
- MimeHtmlText allows the receiving email client to decide the best format to display the message.
Stage 3: change remote domain settings
To change the ContentType property, run the following command:
Set-RemoteDomain -Identity <name> -ContentType <type>
Note: The identity <name> should be populated with the name of the remote domain specified on the Microsoft Exchange Server. By default, this is *. For example:
Set-RemoteDomain -Identity * -ContentType MimeHtml
To set the TNEFEnabled property
When this value is set to $Null (blank), which is the default setting, TNEF messages are not specifically allowed or prevented for recipients in the destination domain. Whether TNEF messages are sent to recipients in the remote domain depends on the specific setting on the mail contact or mail user, or the setting specified by the sender in Outlook.
- Follow instructions for stage 1 (above) to connect to Office 365.
- Run the following command:
Set-RemoteDomain * -TNEFEnabled $Null
For further information, please refer to this MSDN article.