Both (or either) module and screen should be applied &1/&2/&3

What causes this issue?

There is an inconsistency in an interface-specific subscreen that was
defined in Customizing. The selection parameter that is assigned to a
key field cannot be accessed. The reason could be one of the following;
There is no subselection screen assigned for the interface.
Although a subselection screen is assigned to the interface, the screen
does not contain the selection parameter.

System Response

The error handling application is stopped.

How to fix this error?

Contact your system administrator or interface developer.

Procedure for System Administrators

You should check and maintain the module and screen in Customizing for
the SAP Application Interface Framework under <DS>
<DS:SIMG./AIF/ERROR_NS>Namespace-Specific Features</></>.
You should also check the consistency of the assignment of selection
parameters to key fields under <DS>
<DS:SIMG./AIF/ERROR_IF>Interface-Specific Features
</></> in the view <ls>Define Key Fields for Multi. Search</> from the
menu on the left-hand side.

Error message extract from SAP system. Copyright SAP SE.