When you submit products, there are two possible workflows along with Approved; Rejected or Returned.
Rejected
There can be several reasons for the rejection:
The product was submitted but was not accepted by the channel.
The product data was rejected before it was even sent to the channel.
You can determine which of the two scenarios above is happening by looking at the submission log - https://pds.stibosystems.com/#/submission-logs
If the "External Id" is blank, is means that the product was rejected before it was sent to the channel.
If the "External Id" is not blank, then is means that the product was rejected by the channel.
Returned
The item will show as Returned when a product has previously been submitted to a channel but the channel needs more or new information from you.
In either case, the product in question has been bounced back for further review and improvements before it can be accepted.