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# Troubleshooting

> Learn about the error handling for Experiences by Contentful Studio.

## Troubleshoot connection error

After the preview URL is set up, the Experiences canvas might display a "Your website refused to connect" message.

![Connection error](/developers/docs/_fern-img/ee83c8c8a366f454ecc29339e4e748ecf9e3d1bc865676e4f2d42528129c5397.webp)

This can happen if:

* Your project server is not running.
* Your project is running on the wrong port.
* Your preview URL is wrongly configured.
* Your website has a strict security configuration (Security Header or Content Security Policy (CSP)), which prevents other websites from embedding it.

To troubleshoot this:

* Ensure that the project is running and on the correct port.
* Confirm if your preview URL is rightly configured.
* Reach out to your dev or security team to modify your website security configuration.​​

## How to determine the problem area when troubleshooting

Below are described some patterns to help you determine the potential problem area whenever an issue arises:

* A setup issue:
  * Some parts of the Experiences UI are rendering but nothing has changed in specific parts where you expected changes.
  * Some parts of the Experiences UI are rendering but other parts, such as your frontend application rendered in the canvas, aren't displayed at all.
* Experiences UI- or SDK-related issue:
  * Your application renders behaves and renders correctly locally.
  * Your application renders and behaves correctly in the Experiences UI, but then some action causes the
    Experiences UI to crash.
  * The canvas interaction doesn't behave as expected.
  * The layers tab or sidebar doesn't behave as expected.
  * Your application is inconsistent between what is being rendered locally versus the Experiences UI canvas. Particularly, if you've double-checked the elements in the browser console to verify the CSS attributes and values.
* A frontend application issue:
  * Your application doesn't render locally.
  * Your application has bugs or inconsistencies locally.
  * The Experiences canvas itself prints out errors that you see in the terminal.
    ![Frontend application error](/developers/docs/_fern-img/f5bbe59be358b335a62ff941aab169990b6cc26de89ef0cb42bced47d2334517.webp)