Check details
Check if the source database to be migrated no longer exists. If it does not exist, an error will be reported with the error details: "Check if the source database exists".
Fixing Method
If a source database existence check error is reported: "Check whether the source database exists," please confirm whether the database to be migrated exists in the source instance. If it does not exist, you need to reconstruct the migration task. It is recommended not to delete the source database during the migration process.