Valid index was not determined; message table &1 is invalid

What causes this issue?

A valid index was not determined. The message table is invalid.

System Response

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

How to fix this error?

Actions must be taken to create a valid index table. For further
information and assistance, contact your system administrator or
interface developer.

Procedure for System Administrators

As a minimum requirement, the index table must have the following:
Field Name,,Data Type,,Length,,
MSGGUID,,CHAR,,32
You must include the predefined structure into your index table:
Structure Name,,Group Code,,
/AIF/IFKEYS,,KEYS
/AIF/ADMIN,,ADMIN
The table should have at least one index.
The index should have all the key fields as the index components. We
recommend that CREATE_DATE and CREATE_TIME are part of the index
components.
The sequence of index components must follow the sequence of key fields.
Application-specific key fields must have priority.
The field of client ID (for example, MANDT) must be the first field of
the index.

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