Constants that span lines are not allowed

What causes this issue?

You have entered a character sequence in the Formula Builder that
contains a line break between two apostrophes (<ZH>'</>).

How to fix this error?

In the Formula Builder, constants must not contain a line break.
Therefore, remove the line break from the constants. The respective
position has been highlighted in the formula.

Error message extract from SAP system. Copyright SAP SE.