Exchange Server Plain Text: Why Your Emails Aren’t Sending in HTML

If an Exchange server is sending outbound mail in plain text instead of HTML — even though the original messages were composed with formatting — the cause is usually the Remote Domains content-type setting rather than anything client-side.

Checking the current setting

From the Exchange Management Shell, run:

Get-RemoteDomain | fl

Look at the ContentType property in the output. There are three possible values:

• MimeHtml — converts messages to MIME using HTML formatting, unless the original message was plain text, in which case it stays plain text.
• MimeText — converts all outbound messages to plain text formatting, regardless of how they were composed. This is the setting that causes the symptom described above.
• MimeHtmlText — converts all messages to MIME using HTML formatting. This is what you want if you want formatting preserved.

Fixing it

If Get-RemoteDomain shows MimeText, change it with:

Set-RemoteDomain –ContentType MimeHtmlText

If you’re managing the default remote domain specifically, or have multiple remote domain entries configured (e.g. for different partner domains), target each one explicitly by name — Get-RemoteDomain without a name filter will list them all, so check whether the issue is happening on the default entry or a specific one before changing settings server-wide. If you run multiple Exchange servers, apply the same check and fix on each — remote domain settings aren’t necessarily uniform across a multi-server environment unless you’ve deliberately kept them in sync.

Screenshot: Remote Domain ContentType Setting

Still the Right Setting on Current Exchange (2026)

The Remote Domains ContentType setting, and the Get-RemoteDomain/Set-RemoteDomain cmdlets used to check and change it, remain unchanged and current on Exchange Server Subscription Edition (SE) — the current on-premises Exchange release. No rename or deprecation of the cmdlet or the ContentType parameter’s values (MimeHtml, MimeText, MimeHtmlText) has happened, so the steps above apply exactly as written to a current on-prem Exchange server.