> For the complete documentation index, see [llms.txt](https://docs.langstack.com/welcome/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.langstack.com/welcome/get-started/learn-langstack/basics-and-essentials/what-is-an-action/error-propagation.md).

# Error propagation

* Error propagation alerts the users about the error(s) in the application. 
* The error(s) may be in the individual fields, sections, functions, Action boxes, Actions, and Container Actions. 
* There are three (3) main types of error propagation. These are denoted by the following icons: 
  *  ![](/files/Y6d3dkIFfY5jghM6n1Nv): There is a problem in the section/function/field. (contains elements having a problem) 
  * ![](/files/wup0vK4K03OnrylwwhFB) : There is a problem with elements inside this element displaying this icon. (contains elements that are having a problem)
  * ![](/files/bO6JjoNCMuiI92Za0Ewn):  There is a problem with the element displaying the icon. (is problematic itself) 
* When the user clicks on the icon, the tooltip explains the potential problem area.

### Example

The error propagation icons are explained through the following illustration of the error propagation in the “On Skipped record” section in an ETL pipeline: 

* The (icon) says that there is a problem within the “On Skipped record” function.

<figure><img src="https://media.langstack.com/documentation/media/images/code/training_manual/chapter_2/ch2errorpropagation_img1_oneofactionboxescontainserrors.png" alt=""><figcaption></figcaption></figure>

* &#x20; The icon says there is no problem with the Action box, but there is a problem with an Action within the Action box.&#x20;

<figure><img src="https://media.langstack.com/documentation/media/images/code/training_manual/chapter_2/ch2errorpropagation_img2_oneofactionscontainedhaserrors.png" alt=""><figcaption></figcaption></figure>

* &#x20; The icon says there is a problem with the element displaying the icon.

{% embed url="<https://media.langstack.com/documentation/media/images/code/training_manual/chapter_2/ch2errorpropagation_img3_actionitselfhaserrors.png>" %}


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