Select at most one entry.

What causes this issue?

You selected more than one entry.
However, usually only one selected entry is visible, because any other
selected entry (or entries) has disappeared from the screen due to
scrolling.

System Response

The system deletes all selections. The action is not carried out.

How to fix this error?

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

Error message extract from SAP system. Copyright SAP SE.