Product restriction message type is missing.

What causes this issue?

No message type was entered after switching on the restriction for the
product field.

System Response

You must enter a message type.

How to fix this error?

Set the message type to 'E' for error mode, 'W' for warning mode, or
'I' for information mode. This determines the type of message used for
checking the contract restriction on the product field.

Error message extract from SAP system. Copyright SAP SE.