iframe code not working

Sorry, but can you provide some additional details?

I cant see the iframe on the page you posted.
And what kind of update you are refering to?

You won’t be able to see any iframes on my pages because I can’t get them to be added to a post, but i want to.

My point was that when I enter the short code to include on a post and click on the update button to update the already published post the page refreshes to a page saying

Not Acceptable
An appropriate representation of the requested resource /wp/wp-admin/post.php could not be found on this server.

Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.

I think it is not related to the iframe plugin at all.
I think you need to ask the theme or plugin developer who created the update functionality you are referring to.

It’s the update button in wordpress post page. I’ll see if I can do a screen grab to show you.

Screen capture of this issue I’m getting.
[video src="https://gerrylevens.com/workTry/iFrame_WP.mp4" /]

Wow, that is the most weirdest issue I ever seen. Thank you very much for the screen capture.
I tried the same steps and I cant reproduce that. I tried on latest WordPress and latest iframe plugin.
I can suggest for you to try to switch the content editor into the “Text” mode and insert iframe shortcode again, press Update button and see if that solves the issue.

If not, I think you might have some conflict with theme or another plugin.
You can disable plugins one by one and try the same previous steps. This can help you to find the root of the issue.

Thanks, I’ve tried all of what you suggest and still can’t get it going.
I’ve tried another (more complicated) iframe plugin and get the same.

I’m getting a sneaky suspicion it’s something that my host is doing and will raise a ticket with them. Is there anything you’ve come across regarding host issues that I can pass on to them that might guide them to a solution?

Yes, I think it worth raising the ticket to Hosting support if you have same issue even with all the plugins disabled and with default theme.

It was a security restriction by my host. It took a couple of pokes at them before they got down to work. On reviewing what files got changed it looks like work was done on the .htaccess files on the root and inside the wp folder. This might help other users that are having issues.

After that youtube videos worked fine. I then ran into what I thought was another issue because html files on my own site that I wanted iframed was being restricted, but digging around made me realise the read permissions set on the html files were wrong and all seems to work fine now.

Thank you for your help on this.