Let
D
=
G
/
K
D=G/K
be a bounded symmetric domain and
K
/
L
K/L
the Shilov boundary of
D
D
. Let
N
\mathcal {N}
be the Shilov boundary of the Siegel domain realization of
G
/
K
G/K
. We consider the case when
D
D
is the exceptional non-tube type domain of the type
(
e
6
(
−
14
)
,
s
o
(
10
)
×
s
o
(
2
)
)
(\mathfrak {e}_{6(-14)}, \mathfrak {so}(10)\times \mathfrak {so}(2))
. We prove that
(
N
⋊
L
,
L
)
(\mathcal {N}\rtimes L, L)
is not a Gelfand pair and thus resolve an open question of G. Carcano.