Before using the Migration Hub and Application Discovery Service, you need to select a Migration Hub home region from the Migration Hub Settings page or using the Migration Hub Config API. Application Discovery Service uses the Migration Hub home region as the only AWS region to store your discovery and planning data. The data stored in the Migration Hub home region provides a single repository of discovery and migration planning information for your entire portfolio and a single view of migrations into multiple AWS regions. See the docs to learn more about the Migration Hub home region.
Note: Once set, the Migration Hub home region cannot be changed.