Field label for field &1 from infotype &2 is used more than once.

What causes this issue?

You have tried to enter more than one field name for a field. This is
not possible for technical reasons. It is not even possible if the
field names appear in different lines.

System Response

How to fix this error?

Please contact your system administrator.

Procedure for System Administrators

Determine the incorrect entry in Customizing in <LS>Personnel
Administration</> in the <LS>Header Structure per Infotype</> screen in
<DS:SIMG.OHIX0635>Determine Infotype Header</> and correct it.

Error message extract from SAP system. Copyright SAP SE.