> ## Documentation Index
> Fetch the complete documentation index at: https://docs.flowx.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Failed process start (exceptions)

> View and debug exceptions that occur when process instances fail to start, including detailed error information and stack traces.

Exceptions are types of errors meant to help you debug a failure in the execution of a process.

<Frame>
  ![](https://s3.eu-west-1.amazonaws.com/docx.flowx.ai/building-blocks/process/exceptions1.png)
</Frame>

Exceptions can be accessed from multiple places:

* **Failed process start** tab from **Active process** menu in FlowX.AI Designer.
* **Process Status** view, accessible from **Process instances** list in FlowX.AI Designer.

<Frame>
  ![](https://s3.eu-west-1.amazonaws.com/docx.flowx.ai/building-blocks/process/exceptions2.png)
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<Hint>
  If you open a process instance and it does not contain exceptions, the **Exceptions** tab will not be displayed.
</Hint>

### Exceptions data

When you click **view** button, a detailed exception will be displayed.

<Frame>
  ![](https://s3.eu-west-1.amazonaws.com/docx.flowx.ai/building-blocks/process/exceptions_data.png)
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* **Process Definition**: The process where the exception was thrown.
* **Source**: The source of the exception (see the possible type of [sources](#possible-sources) below).
* **Message**: A hint type of message to help you understand what's wrong with your process.
* **Type**: Exception type.
* **Cause Type**: Cause type (or the name of the node if it is the case).
* **Process Instance UUID**: Process instance unique identifier (UUID).
* **Token UUID**: The token unique identifier.
* **Timestamp**: The default format is - `yyyy-MM-dd'T'HH:mm:ss.SSSZ`.
* **Details**: Stack trace (a **stack trace** is a list of the method calls that the process was in the middle of when an **Exception** was thrown).

#### Possible sources

<CardGroup>
  <Card title="Actions" href="../../../building-blocks/actions/actions" />

  <Card title="Node" href="../../../building-blocks/node/node" />

  <Card title="Subprocess" href="../../../building-blocks/process/subprocess" />

  <Card title="Process Definition" href="../../../building-blocks/process/process-definition" />
</CardGroup>

### Exceptions type

Based on the exception type, there are multiple causes that could make a process fail. Here are some examples:

| Type                     | Cause                                                                                                                                                                                                              |
| :----------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| Business Rule Evaluation | When executing action rules fails for any reason.                                                                                                                                                                  |
| Condition Evaluation     | When executing action conditions.                                                                                                                                                                                  |
| Engine                   | <p /><p>When the connection with the database fails</p><p>when the connection with [Redis](../../../platform-overview/frameworks-and-standards/event-driven-architecture-frameworks/intro-to-redis) fails</p><p /> |
| Definition               | Misconfigurations: process def name, subprocess parent process id value, start node condition missing.                                                                                                             |
| Node                     | When an outgoing node can’t be found (missing sequence etc).                                                                                                                                                       |
| Gateway Evaluation       | <p>When the token can’t pass a gateway for any reason, possible causes:</p><ul><li>Missing sequence/node</li><li>Failed node rule</li></ul>                                                                        |
| Subprocess               | Exceptions will be saved for them just like for any other process, parent process ID will also be saved (we can use this to link them when displaying exceptions).                                                 |