> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://help.aads.com/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# Ad Unit Error: Missing URL in Ad Unit HTML Code

The error "Missing URL in HTML" occurs when the `src` attribute of the iframe tag is absent or empty. This can happen, for example, if you edited your ad unit code and accidentally removed the `src` attribute.

If you add a URL to the `src` attribute using JavaScript, it may not be added in time for the bot to recognize it, resulting in the URL being defined as empty.

| A correct src attribute loos like this:
| ![](https://storage.crisp.chat/users/helpdesk/website/-/6/a/9/5/6a953c4814a02400/image_1mrftma.png =300x295)

||| **Important:** Earnings at AADS are only generated after an ad unit has been successfully detected by our system.
||| If an ad unit is not found (for example, due to incorrect installation, caching, blockers, or loading issues), impressions cannot be counted and no revenue can be accrued for that period.
||| For this reason, we strongly recommend verifying that the ad unit is detected immediately after installation and after any website changes.

If you have any questions about our platform, feel free to [contact our support team](https://help.aads.com/). We’re here to help 24/7.