  The description of complex solvable Leibniz algebras whose nilradical is a
naturally graded filiform algebra is already known. Unfortunately, a mistake
was made in that description. Namely, in the case where the dimension of the
solvable Leibniz algebra with nilradical $F_n^1$ is equal to $n+2$, it was
asserted that there is no such algebra. However, it was possible for us to find
a unique $(n+2)$-dimensional solvable Leibniz algebra with nilradical $F_n^1$.
In addition, we establish the triviality of the second group of cohomology for
this algebra with coefficients in itself, which implies its rigidity.
