Why is my selection failing with a 'Automation/Query Failed due to system error,' and how can I resolve it?

The “Automation/Query Failed due to system error” is an SFMC error that typically occurs when there is a mismatch in the Data Extensions' configurations. Specifically, if the Target Data Extension has a field configured to a smaller length than the source or mapped data, the system will throw this error.

In case your Selection is failing due to a system error, here a possible ways to solve it.

How to resolve this?

1. Check Field Lengths in the Target Definition step: Ensure that the length of the fields in the Target DE matches or exceeds the length of the corresponding fields in the source DE.
2. Verify Data Types: Confirm that the data types of the mapped fields are compatible.
3. Update Target DE: If necessary, modify the Target DE to increase the length of the fields that are causing the issue. 
   1. Go to the Data Extension itself in Email Studio and increase the field length of the fields.
   2. Go to DESelect Segment, open the Selection, and try to re-run the Selection.

If the problem persists after these checks, you might need to contact SFMC support for further assistance.

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