Define an operator

What causes this issue?

You have not yet defined a comparison operator for the selection
condition.

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?

Select a comparison operator. You can display the valid comparison
operators by pressing the F4-button in the field <LS>Op.</>

Error message extract from SAP system. Copyright SAP SE.