Issue
An application fails to start with a CRITICAL error indicating that com.mendix.storage.s3.Region is required but not set.
2026-02-12 13:09:39.848 CRITICAL - StorageS3: com.mendix.storage.s3.Region is required but not set. ... Caused by: software.amazon.awssdk.core.exception.SdkClientException: Unable to load region from any of the providers in the chain software.amazon.awssdk.regions.providers.DefaultAwsRegionProviderChain...
Environment
- Studio Pro 10.24.14 and newer
- Studio Pro 11.6.0 and newer
- Studio Pro 9.24.41 and newer
Cause
This issue is caused by a breaking change introduced in the versions listed above. In these releases, the underlying Amazon S3 SDK library that Mendix uses for its file storage backend was upgraded from version 1 to version 2.
The new AWS S3 SDK v2 has stricter configuration requirements and will not function if an S3 region is not specified. This makes the com.mendix.storage.s3.Region custom runtime setting mandatory for all S3-compatible connections.
For S3-compatible providers like MinIO or Google Cloud Storage, which do not use AWS regions, a valid region must still be provided for the SDK to sign requests correctly. These services will typically accept any value as long as it is formatted like a standard AWS region. The value us-east-1 is a common and safe choice in these scenarios.
Solution/Workaround
To resolve this issue, add the com.mendix.storage.s3.Region custom setting to the Mendix application's configuration:
- Add the
com.mendix.storage.s3.Regioncustom setting to the application configuration. - For S3-compatible providers like MinIO or Google Cloud Storage, the region value can be set to any valid AWS region string, for example,
us-east-1. The important part is that the setting is present. - If using
com.mendix.storage.s3.EndPoint, ensure it is either not set or set to an endpoint matching the region. - Redeploy the application.
After adding this setting and redeploying the application, the connection to the storage should work correctly.
Internal information related
271907
C3T260XGA/p1766500425081769
Additional information
Mendix documentation:
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