No error message for IDoc number: &

What causes this issue?

You have selected the function <LS>Messages long text</>. There is no
error message for the IDoc number specified above.

System Response

A long text on the message cannot be displayed.

How to fix this error?

If necessary, choose a message with an error number. If an error number
is available, it is displayed in the list under the column 'Error
number' for the respective IDoc number.

Error message extract from SAP system. Copyright SAP SE.