Please check the workflow status of the scheme to ensure that the trading partner should definitely be able to currently see it.
Also ensure that the trading partner has accepted the invite to Collaborate with you, they may be on Collaborator but have not accepted the tile invite. To check this, go into the collaborator tab and view the invite status. If the status is red, the collaborator has been invited but not accepted. If the status is green, the collaborator has been invited and accepted.
If you are unable to resolve the issue with your trading partner and they are still experiencing a technical issue, please instruct them to: