How To Fix WL492 - Comparison cannot be evaluated since element/expression '&' has no value

SAP Error Message - Details

• Message type: E = Error

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

• Message number: 492

• Message text: Comparison cannot be evaluated since element/expression '&' has no value

How to fix this error?

Make sure that the workflow/work item variables involved or object
attributes are assigned a value. Variables can be assigned values
from the result parameters of a work item (by binding)
by an assignment (container operation)
by pre-assignment (initial values) at the start of the workflow/work
item.
If the variables involved still do not contain any data, there may be
an error in the definition or when carrying out the binding.

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