How To Fix SY421 - Specified comparison operator is not permitted

SAP Error Message - Details

• Message type: E = Error

• Message class: SY - ABAP/4 system messages

• Message number: 421

• Message text: Specified comparison operator is not permitted

What causes this issue?

You may only use one of the following comparison operators with
conditional watchpoints:

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

>, >=, =, <>, <, >=
The operator that you used here is not allowed.

System Response

How to fix this error?

Use one of the above comparison operators instead.
If you do not use a comparison operator, the debugger will stop
whenever the value changes.

Error message extract from SAP system. Copyright SAP SE.