[Mail] email not being sent it using sendHtmlMailWithAttachments option

[ubeaut]

Expected Behavior

Email should send with attachments and be in HTML format.
If I use sendHtmlMail option the mail is sent and is in HTML format.

Current Behavior

Email send a warning to the log and email is not sent.
[2023-08-22 19:00:14.706 [WARN ] [ab.binding.mail.internal.SMTPHandler] - javax.mail.MessagingException: IOException while sending message;
nested exception is:
javax.activation.UnsupportedDataTypeException: text/plain; charset=UTF-8

Possible Solution

Currently I just send the email and attachments and use plain text.

Steps to Reproduce (for Bugs)

This doesn't work:

var message = "<H2>Someone is at the front gate at " + Date() + "</H2>";
var attachmentUrlList = ["http://192.168.1.164/zm/cgi-bin/zms?mode=single&monitor=1&scale=50",
                         "http://192.168.1.164:8080/static/graphviz.png"];

actions.get("mail", "mail:smtp:a514b96247").sendHtmlMailWithAttachments("xxxxxxx@gmail.com", "openHAB 4 front gate IR", message, attachmentUrlList);

This works:

var message = "<H2>Someone is at the front gate at " + Date() + "</H2>";
var attachmentUrlList = ["http://192.168.1.164/zm/cgi-bin/zms?mode=single&monitor=1&scale=50",
                         "http://192.168.1.164:8080/static/graphviz.png"];

actions.get("mail", "mail:smtp:a514b96247").sendMailWithAttachments("xxxxxxx@gmail.com", "openHAB 4 front gate IR", message, attachmentUrlList);

Context

I have mentioned it in the forum here:
https://community.openhab.org/t/oh4-sending-email-as-html-with-attachent-javascript-not-dsl/148951

Your Environment

• Version used: (e.g., openHAB and add-on versions) OH4.0.2
• Environment name and version (e.g. Chrome 76, Java 8, Node.js 12.9, ...):
• Operating System and version (desktop or mobile, Windows 10, Raspbian Buster, ...):

Operating system Linux/6.1.0-11-amd64 (amd64)
Java Runtime Azul Systems, Inc. 17.0.7 (Zulu17.42+19-CA)

[OmegaQuest]

I also get this same exact error but only when trying to send via: sendHtmlMailWithAttachment

sendHtmlMail works fine and so does sendMailWithAttachment just not the "Html" option with Attachment

OpenHAB v 4.2.0 M1
17.0.10 (Zulu17.48+15-CA)
Ubuntu 22.04.4 LTS