Troubleshooting error message

I’m receiving an error message when I try and embed an iframe and I don’t know how to diagnose the problem.
Below are some screenshots. Any help is appreciated.

Could you post your blueprint please?

This is the blueprint:

    label: Vimeo Links
    type: structure
    entry: >
      {{vimeovid}}<br />
         label: Vimeo
         type: text

Do you get the same error if you just put text into the field? I can’t reproduce this issue.

Seems like your indentation is not quite correct, but I don’t know if that causes the error.

Do you use any custom fields in the same blueprint?

Putting in text works fine. The indentation is correct in the actual code, that’s just the way it copied.

What do you mean by custom fields?

I meant third party fields that could interfere.

Could you post the iframe that causes the problem?

And which Kirby version, PHP version are you using?

I have the wysiwyg text editor.
The iframe is any vimeo embed frame.
Kirby is running on 2.4.1 and the PHP version is PHP 5.6.25.

when I add a the vimeo iframe locally is works fine. It is only when trying to add the video on the live site it comes up with that error

Can you add any other html tags?

An alternative would be to put the URL into the text field and use the kirbytag helper together with the Vimeo kirbytag to render the video on the frontend. Or to use the Vimeo kirbytag and render via kirbytext.

yes, other elements work without a problem.

I did this instead.

<div id="vimeoVid">
       <iframe src="<?php echo $vimeovid['vimeovid'] ?>?title=0&byline=0&portrait=0" width="640" height="360" frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen>

which works by just pasting the number in.
Thanks for looking into it, Kirby is a great community.