Duplicate ID error

Overview

The Duplicate ID error means that another element exists in the code with the same ID as one on the indicated line. The site's HTML requires that each element has it's own unique ID value assigned to it. If you have two elements with the same ID value -- The system will return an error when trying to save the HTML file.

How can I fix this?

Change the ID of the element on the indicated line to a unique ID.

Example

If I copy an image's code, expecting to display the image twice, Developer mode will throw this error.

<img id="1591034424" src="https://dd-cdn.multiscreensite.com/themes/blank-regular/blank-regular-hp-main-image.png" />
     <img id="1591034424" src="https://dd-cdn.multiscreensite.com/themes/blank-regular/blank-regular-hp-main-image.png" />

To fix this, change the ID to something else with the same ID length:
<img id="1591034424" src="https://dd-cdn.multiscreensite.com/themes/blank-regular/blank-regular-hp-main-image.png" />
     <img id="1644664466" src="https://dd-cdn.multiscreensite.com/themes/blank-regular/blank-regular-hp-main-image.png" />