application/pgp-signature is unsupported

[Joseph]

I'm missing a setting I think.
When I open gpg signed message I get:
application/pgp-signature is unsupported (use 'v' to view ...

mutt pgp setting:
# automatically verify the sign of a message when opened
set crypt_verify_sig=yes

mailcap
application/pgp-signature; gpg %s

What am I missing? 

--
Joseph