Unfortunately, this is a limitation of the UCCX server and the way it implements its mail client. More specifically, the Content-Type header it sends to the email server.
E.g.,
Date: Wed, 13 Feb 2019 12:31:57 -0600
From: <uccx@company.com>
To: <anthony@company.com>
Message-ID: <26014177.183.1550082717398.JavaMail.uccxuser@uccxpub>
Subject: Finesse: Caller(s) Waiting in CSQ anthony!
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
X-Mailer: Cisco Customer Response Solutions
Content-Language: en-US
Return-Path: uccx@company.com
If you really want this to happen, you might have some luck with the following two links:
This link shows how it might be possible to send an email from UCCX without using the limiting Send eMail step.
https://community.cisco.com/t5/collaboration-voice-and-video/uccx-quick-java-recipes/ta-p/3113801#mailjava
This link shows how it might be possible to send a multi-part HTML mime message of type text/html:
https://en.wikipedia.org/wiki/JavaMail#Examples
I've never done this before. I'm just pulling together some information for you. Good luck, and if you figure it out, please post your solution, as I'm curious to know what a final product looks like.
