Only parameters which do not occur in table TPARA are allowed

What causes this issue?

You have entered a parameter name which is already encrypted in table
TPARA.

System Response

The parameter name has already been assigned. You cannot use the same
name several times or applications will overwrite each others
parameters.

How to fix this error?

Choose a parameter name which has not yet been encrpyted in TPARA.

Error message extract from SAP system. Copyright SAP SE.