Hello!
I try to display external https webpage in splunk dashboard panel - but have SSL_PROTOCOL_ERROR
I use iframe module:
<dashboard>
<label>My Dashboard</label>
<row>
<html>
<h2>Embedded Web Page!</h2>
<iframe src="https://10.8.128.23:8787" width="100%" height="800">></iframe>
</html>
</row>
</dashboard>
Below is a sample of the code I have used. I noticed you have an extra close tag (>) between you iframe tag and your close iframe tag.
<row>
<panel>
<title>Testing HTML</title>
<html>
<iframe src="http://www.splunk.com" height="200" width="1000" style="border:none;"></iframe>
</html>
</panel>
</row>