The error "RETURN_ADDRESS_CARRIER_ID_IS_MANDATORY" can be found in the PlentyONE log under the integration: Plenty\Modules\Otto\Order\Services\SendShippingConfirmationService and the level: CRITICAL.

This error occurs when multiple return warehouse locations and/or return shipping service providers (return carriers) are stored in the return settings of your OTTO Market backend (OPC). In this case, OTTO requires a tracking ID, which is currently not yet integrated in PlentyONE (implementation expected in Q2 2026).

Solution

To fix the problem immediately and to enable the shipping notification again, the configuration in your OPC must be adjusted:

1. Remove the second return warehouse location and/or the second return shipping service provider from your return shipping settings in the OTTO Market backend (OPC). How to do this is explained here under point 13.

2. Make sure that only one return warehouse and one return shipping service provider is configured.

Trigger shipping notification again

After the correction, you can execute the shipping notification for the affected orders again:

• Trigger the event action with the action “Report shipping information to OTTO” again.

• Depending on the configuration of the event action, the triggering event (e.g. order status) may need to be reversed first and then set again.