# Destination Connection Error Reference

Stitch periodically performs checks on the connection to your destination to ensure the connection remains active and healthy. Below are some of the most common errors you might see if Stitch has trouble performing the connection check to your destination and how to resolve them.

In this reference:

* [Common connection errors](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#common-error-reference)

* [Amazon S3 connection errors](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#amazon-s3-error-reference)

## Common connection errors

The following errors are applicable to all destinations:

* [An I/O error occurred while sending to the backend.](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#io-error)
* [Connection refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#connection-refused)
* [Connection timed out.](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#time-out)
* [FATAL: Password authentication failed for user \[user_name\]](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#password-auth)
* [We encountered an error while attempting to check the type or version for this destination. Please select the correct destination...](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#database-type)
* [We encountered an internal error while checking the connection.](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#internal-error)

### I/O error

```
An I/O error occurred while sending to the backend.
```

`An I/O error occurred while sending to the backend.`An I/O error occurred while sending to the backend.

| **Applicable to** | Amazon Redshift and PostgreSQL-backed destinations |
| --- | --- |
| **Level** | Critical<br><br>the Remove icon<br><br>Data can't be replicated and intervention is required. Stitch will continue to re-try extraction based on the integration's schedule, but replication will not be successful until the issue is resolved. |
| **Category** | Communication |
| **Potential cause(s)** | A transient communication error with the database occurred. |
| **Suggested action(s)** | If this error persists, refer to [these troubleshooting tips](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/aws-io-errors) to diagnose and treat the issue. |

[Back to Common error list](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#common-error-reference)  
[Back to top](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#)

### Connection refused

```
Connection refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
```

`Connection refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.`Connection refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.

| **Applicable to** | All destinations |
| --- | --- |
| **Level** | Critical<br><br>the Remove icon<br><br>Data can't be replicated and intervention is required. Stitch will continue to re-try extraction based on the integration's schedule, but replication will not be successful until the issue is resolved. |
| **Category** | Communication |
| **Potential cause(s)** | Stitch is unable to connect to the destination. This is typically a result of incorrectly entering connection details into Stitch, or a failure to whitelist Stitch’s IP addresses. |
| **Suggested action(s)** | <ul> <li>Verify that the <strong>hostname</strong> entered in the Destination Settings page is correct.</li> <li>Verify that the <strong>port</strong> entered in the Destination Settings page is correct.</li> <li> <p>Verify that Stitch’s IP addresses are whitelisted.</p> <p><strong>For Amazon RDS databases</strong>: Check that the Security Group and VPC Subnet associated with the database allows access from all Stitch’s IP addresses.</p> </li></ul> |

[Back to Common error list](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#common-error-reference)  
[Back to top](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#)

### Connection timeout

```
Connection timed out.
```

`Connection timed out.`Connection timed out.

| **Applicable to** | All destinations |
| --- | --- |
| **Level** | Critical<br><br>the Remove icon<br><br>Data can't be replicated and intervention is required. Stitch will continue to re-try extraction based on the integration's schedule, but replication will not be successful until the issue is resolved. |
| **Category** | Communication |
| **Potential cause(s)** | The connection to the destination timed out before Stitch could successfully establish a connection. |
| **Suggested action(s)** | This error may be transient and resolve on its own, but if it persists, try the following before contacting support:<br><br><ul> <li>Verify that the <strong>hostname</strong> entered in the Destination Settings page is correct.</li> <li>Verify that the <strong>port</strong> entered in the Destination Settings page is correct.</li></ul> |

[Back to Common error list](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#common-error-reference)  
[Back to top](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#)

### Incorrect password for database user

```
FATAL: Password authentication failed for user [user_name]
```

`FATAL: Password authentication failed for user [user_name]`FATAL: Password authentication failed for user [user\_name]

| **Applicable to** | All destinations |
| --- | --- |
| **Level** | Critical<br><br>the Remove icon<br><br>Data can't be replicated and intervention is required. Stitch will continue to re-try extraction based on the integration's schedule, but replication will not be successful until the issue is resolved. |
| **Category** | User credentials |
| **Potential cause(s)** | The credentials for the database user authorizing the connection are incorrect. |
| **Suggested action(s)** | Verify that the password entered into the Destination Settings page for the authorizing user is correct. |

[Back to Common error list](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#common-error-reference)  
[Back to top](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#)

### Database type mismatch

```
We encountered an error while attempting to check the type or version for this destination. Please select the correct destination type and try again.
```

`We encountered an error while attempting to check the type or version for this destination. Please select the correct destination type and try again.`We encountered an error while attempting to check the type or version for this destination. Please select the correct destination type and try again.

| **Applicable to** | All destinations |
| --- | --- |
| **Level** | Critical<br><br>the Remove icon<br><br>Data can't be replicated and intervention is required. Stitch will continue to re-try extraction based on the integration's schedule, but replication will not be successful until the issue is resolved. |
| **Category** | Incorrect Stitch setup |
| **Potential cause(s)** | The destination type doesn’t match the destination you selected in Stitch.<br><br>For example: You select Amazon Redshift in Stitch, but we detect that it’s actually a PostgreSQL database. |
| **Suggested action(s)** | Verify that you’ve selected the correct destination type. If the incorrect destination type was chosen, select the correct destination type and try completing the setup again. |

[Back to Common error list](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#common-error-reference)  
[Back to top](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#)

### Internal error

```
We encountered an internal error while checking the connection.
```

`We encountered an internal error while checking the connection.`We encountered an internal error while checking the connection.

| **Applicable to** | All destinations |
| --- | --- |
| **Level** | Critical<br><br>the Remove icon<br><br>Data can't be replicated and intervention is required. Stitch will continue to re-try extraction based on the integration's schedule, but replication will not be successful until the issue is resolved. |
| **Category** | Internal |
| **Potential cause(s)** | Stitch encountered an internal issue. |
| **Suggested action(s)** | This error is usually transient and will resolve on its own, but if it persists, check our [Status Page](https://status.stitchdata.com/) for reported service outages. |

[Back to Common error list](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#common-error-reference)  
[Back to top](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#)

## Amazon S3 connection errors

* [An error occurred (404) when calling the HeadObject operation: Not Found](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#missing-challenge-file)

### Missing challenge file

```
An error occurred (404) when calling the HeadObject operation: Not Found
```

`An error occurred (404) when calling the HeadObject operation: Not Found`An error occurred (404) when calling the HeadObject operation: Not Found

| **Applicable to** | Amazon S3 destinations |
| --- | --- |
| **Level** | Critical<br><br>the Remove icon<br><br>Data can't be replicated and intervention is required. Stitch will continue to re-try extraction based on the integration's schedule, but replication will not be successful until the issue is resolved. |
| **Category** | Destination setup |
| **Potential cause(s)** | This error occurs when the Stitch [challenge file](https://help.qlik.com/en-US/stitch/destinations/amazon-s3/connecting-an-amazon-s3-data-warehouse-to-stitch#verify-bucket-access) isn’t found in the specified S3 bucket.<br><br>The challenge file is used to test Stitch’s connection to the bucket. Stitch will surface this error if it cannot find the challenge file, whether because the file was removed or never created. |
| **Suggested action(s)** | <ul> <li><strong>If you still have access to the challenge file name</strong>, follow <a href="https://help.qlik.com/en-US/stitch/destinations/amazon-s3/connecting-an-amazon-s3-data-warehouse-to-stitch#verify-bucket-access">these instructions</a> to create the file in your S3 bucket.</li> <li> <p><strong>If you no longer have access to the challenge file name</strong>, you’ll need to create a new S3 destination <a href="https://help.qlik.com/en-US/stitch/destinations/switching-destinations">using these instructions</a>.</p> <p><strong>Note</strong>: Creating a new destination doesn’t mean you’ll need to re-replicate all of your data. During the destination change process, you can choose to pick up replication where it left off or to queue a historical re-replication.</p> </li></ul> |

[Back to Amazon S3 error list](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#amazon-s3-error-reference)  
[Back to top](https://help.qlik.com/en-US/stitch/troubleshooting/destinations/destination-connection-error-reference#)