Message type: E = Error
Message class:  TR - Change and Transport System 
Message number: 607
Message text: Specify both systems belonging to the delivery
Fewer than two systems were entered during delivery maintenance.
A delivery must always consist of two systems:
System to be delivered to
System that delivers to the other system
The system issues an error message and will not allow you to continue with this transaction until the error is resolved.
Enter both systems.
Error message extract from SAP system. Copyright SAP SE.
The SAP error message TR607 ("Specify both systems belonging to the delivery") typically occurs in the context of transport requests when you are trying to perform a transport operation (like releasing or importing a transport request) that involves multiple systems, but the system configuration does not specify the source and target systems correctly.
Cause:
Missing Configuration: The transport route between the source and target systems is not properly configured in the Transport Management System (TMS).
Incorrect Transport Request: The transport request may not be correctly assigned to the systems involved in the delivery.
Transport Layer Issues: The transport layer may not be set up correctly, or the systems may not be assigned to the correct transport layer.
Solution:
Check Transport Route Configuration:
Go to the TMS configuration (transaction code STMS).
Navigate to the Transport Routes and ensure that the source and target systems are correctly defined in the transport route.
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