How To Fix WL491 - Operator '&' not allowed or blank in expression '& & &'

WL491 - Overview

• Message type: E = Error

• Message class: WL - Workflow: run-time messages

• Message number: 491

• Message text: Operator '&' not allowed or blank in expression '& & &'

What causes this issue?

The operator &V1& is not supported.

How to fix this error?

The F4 input help in the Workflow Builder lists all operators which are
supported in the current release. Choose one of the operators allowed.

Error message extract from SAP system. Copyright SAP SE.

WL491 - Details

• The SAP error message WL491 indicates that there is an issue with the use of the logical operator & in an expression within a selection screen or a report. This error typically arises when the expression is not correctly formed, leading to an invalid logical operation.
  
  Cause:
  
  
  Incorrect Use of Logical Operators: The error occurs when the logical operator & (AND) is used incorrectly in an expression. This can happen if:
  
  There are too many & operators without corresponding conditions.
  One or more of the conditions are blank or not defined.
  The syntax of the expression is incorrect.
  
  
  
  Blank Conditions: If any of the conditions in the expression are blank, the system cannot evaluate the expression properly, leading to this error.
  
  
  
  Solution:
  
  
  Check the Expression: Review the expression where the error occurs. Ensure that:
  
  Each & operator is followed by a valid condition.
  There are no extra & operators without corresponding conditions.
  
  
  
  Define All Conditions: Make sure that all conditions in