Tehre is confusion in the web from what I could gather about using the shortcode that you mention in your frame.
for example some people have confused this:
[iframe src=”https://www.youtube.com/embed/A3PDXmYoF5U” width=”100%” height=”480″] shortcode
I mean many people think “shortcode” is part of the code.
there are many websites that mention the use of:
<iframe></iframe>
<embed></embed>
[iframe][/frame]
[embed][/embed]
Just be more clear and specific. Basically write the instructions as if an 8 year old child could understand them.
For example:
Step one:
Insert following code in your post. Do so in the “Text” mode (tab):
[iframe -embed code -]
Do not include the word “shortcode” after it.
Step two:
Get the embed code of the video you want to insert in your post.
Step three:
paste the embed code, example:
[iframe width=”640″ height=”360″ src=”https://mpora.com/videos/AAdhxpnoyksk/embed?hd=1″ frameborder=”0″ allowfullscreen]
– this code looks very different from the simple youtube code on your example, you could show both.