You are not authorized to assign roles &3

What causes this issue?

IF &V1& <> &V1(0)& AND &V2& <> &V2(0)&
You are not authorized to assign the role <ZH>&V1&</> to user <ZH>&V2&
</> or to cancel the assignment.
ELSEIF &V1& = &V1(0)& AND &V2& <> &V2(0)&
You are not authorized to assign roles to user <ZH>&V2&</> or to cancel
the assignment.
ELSEIF &V1& <> &V1(0)& AND &V2& = &V2(0)&
You are not authorized to assign role <ZH>&V1&</> to users or to cancel
the assignment.
ELSEIF &V1& = &V1(0)& AND &V2& = &V2(0)&
You are not authorized to assign roles to users or to cancel the
assignment.
ENDIF

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.