Data selection status = &

What causes this issue?

Data selection status:

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

0:,,Data request received
1:,,Data selection started (scheduled in the batch)
2:,,Data selection running
5:,,Error occurred in the data selection
6:,,Transfer structures do not agree (data obsolete)
8:,,No data available for this selection, data selection finished
9:,,Data selection finished

Error message extract from SAP system. Copyright SAP SE.