Then please give the full HTML-code in your Post you are using....
and mention the EXACT error-message and/or "Oops.."-message
If you present code do the following....
edit your Post
- leave one blank-line above of your code
- select your code in the Post
- then =click= on the </>-symbol-of-this-editor
Your code will then be in a pre-code state
and you will be able to make/present the proper indentations.
or even better use