How To Fix WL390 - Expression '&' does not contain a date or time or has errors

WL390 - Overview

• Message type: E = Error

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

• Message number: 390

• Message text: Expression '&' does not contain a date or time or has errors

What causes this issue?

The expression '&V1&' was specified as a reference point for the
deadline calculation for activity no. &V3&. This expression either
contains no (valid) date or no time or contains an error and therefore
cannot be evaluated.
Note: The internal ABAP type of the expression was &V2&, its content
&V4&.

System Response

For the deadlines "latest end, desired start, latest start, desired
end" a warning is logged and a work item is created without these
deadlines.

How to fix this error?

Check the expression concerned in the workflow definition and ensure
that its value is a correct date or a time.
If a work item has been created without (a) deadline(s), you can set
this/these subsequently.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message WL390 - Expression '&' does not contain a date or time or has errors ?

  The SAP error message WL390, which states "Expression '&' does not contain a date or time or has errors," typically occurs in the context of SAP workflows or when dealing with date and time expressions in various SAP modules. This error indicates that the system is unable to interpret the expression provided, either because it is not formatted correctly or because it does not contain valid date or time information.
  Causes:
  
  Incorrect Expression Syntax: The expression may have been entered incorrectly, leading to syntax errors.
  Invalid Date/Time Format: The date or time format used in the expression may not be recognized by SAP.
  Missing Date/Time Values: The expression may be missing required date or time components.
  Data Type Mismatch: The expression may be trying to use a non-date/time field in a context that requires a date/time value.
  Workflow 
  Configuration Issues: If this error occurs in a workflow, it may be due to incorrect configuration or missing