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Datasource Errors

Appsmith provides the ability to connect to a variety of datasources, including both databases and APIs. However, when setting up a new datasource or modifying an existing one, you may encounter connectivity errors. This guide aims to help you troubleshoot and resolve common datasource connectivity errors.

SSL connection error​

dev.miku.r2dbc.mysql.client.MySqlConnectionClosedException: Connection unexpectedly closed. Error was received while reading the incoming data. The connection will be closed.

This error message indicates that the database server that you are trying to connect to does not support SSL. This error can be resolved by editing the SSL field in the datasource and setting it to Disabled.

Error connecting to local database or API​

If you are trying to connect to a local database from Appsmith and see an error message like:

Connection refused. Server logs - 'io.netty.channel.AbstractChannel$AnnotatedConnectException: finishConnect(..) failed: Connection refused: /172.17.0.1:3306'

Cause​

When running Appsmith inside a Docker container, it may have its own network namespace and won't be able to access services running on the host machine using the localhost or 127.0.0.1 addresses. This is because these addresses points to the container's local network, which is different from that of the host machine.

Solution​

Instead, you can use the hostname host.docker.internal on Windows and macOS hosts, and 172.17.0.1 on Linux hosts, to access services running on the host machine from within the container.

Learn more about how to connect to a localhost database / API

Secret key required error​

Secret key is required when sending session details is switched on, and should be at least 32 characters in length.

This message indicates that Send Appsmith signature header field has been marked as Yes but the Session Details Signature Key field is left empty.

This error can be resolved by filling in the Session Details Signature Key field or by disabling the Send Appsmith signature header field by selecting No.

Malformed request error​

malformed request

This message appears when authorizing a Google Sheets datasource with selected sheet access on a self-hosted Appsmith instance.

Cause​

This issue occurs when the self-hosted Appsmith instance is not configured with SSL (HTTPS).

Google’s File Picker API requires a secure connection to return the selected sheet identifiers. In the absence of HTTPS, the request to the file picker fails, resulting in a malformed request error. As a fallback, Appsmith proceeds to authorize access to all sheets, even if only specific sheets were selected during the authorization flow.

Solution​

To resolve this issue, ensure that your self-hosted Appsmith instance is configured to use HTTPS by setting up a custom domain and installing an SSL certificate.

See how to Configure a custom domain and SSL certificate.

Once HTTPS is enabled, the Google File Picker will function correctly, and access will be granted only to the selected sheets as expected.