An intra-org migration is moving the same domain from on-premise to the cloud. The domain name does not change so it is, in essence, both the Source and Destination domain.
Unfortunately, although we do support on-premise to cloud migrations, CloudM Migrate does not support intra-org migrations as we migrate from one domain to another (e.g. cloudm.co to cloudm.io).
If you need to conduct an Intra-Org migration between On-premises Microsoft Exchange and Cloud hosted Microsoft 365 platforms, we would recommend using Microsoft's own MRS process, which enables the MRS proxy endpoint for remote moves in Exchange Server.