REST API: Add Leads to List - Import completed with errors.

Hi,

I'm using the REST API to import leads (email only) into a list.  The import responses with a success status and i get a batchId.  However, when i check the status of the batchId, this is the response i get:

{
  "requestId": "xxxxxxxx",
  "result": [{
    "batchId": 55555,
    "status": "Complete",
    "numOfLeadsProcessed": 0,
    "numOfRowsFailed": 202,
    "numOfRowsWithWarning": 0,
    "message": "Import completed with errors, 0 records imported (0 members), 202 failed"
  }],
  "success": true
}

I check my notification area but there's no information on why the import failed.  Any idea what the issues is or how I can find out what is missing?

thanks