Message type: E = Error
Message class:  VCH_HL_LOVC2AVC_COPY - Messages of LO-VC to AVC Model Copying process 
Message number: 018
Message text: Constraint net &3: Assignment of constraint &1 (&2) failed
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The SAP error message VCH_HL_LOVC2AVC_COPY018 typically indicates a problem related to the assignment of constraints in the context of variant configuration (VC). This error occurs when there is an issue with the assignment of a constraint to a specific object or configuration.
Cause: The error message can be triggered by several factors, including: Incorrect Constraint Assignment: The constraint you are trying to assign may not be compatible with the object or configuration you are working with. Missing Dependencies: There may be missing dependencies or prerequisites that need to be fulfilled before the constraint can be assigned. Data Inconsistencies: There could be inconsistencies in the data related to the configuration or constraints, such as incorrect settings or missing entries. Configuration Settings: The configuration settings for the variant may not be set up correctly, leading to conflicts when trying to assign constraints.
Solution: To resolve the error, you can take the following steps: Check Constraint Definition: Review the definition of the
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