PGP and outlook - Recipient's email not recognised

[Jay]

When I select 'Encrypt Now' or 'Encrypt on Send', the PGP dialog comes up
with no pgp keys in the lower list of recipients. Until very recently, it
would automatically select the pgp keys from recipients and if they were all
signed, continue automatically. Now I have to manually drag each key into
the lower box.

It appears it is not recognising the email addresses for some reason, even
my own (I have the 'Encrypt to default key') option set.

Any idea what might be going on? As I sais, it always used to work fine.

Thanks!

Jay.