You didn't tell us whive version of voicemail you have, Partner Mail, Partner Mail VS, Partner Messaging, Partner Voice Messaging, etc.
But I would suspect that your version has the option to set a mailbox to Answer Only.
Log into mailbox 10 and see if there is an option 8, to set Call Answer Mode, and if so, see if it is set to Answer Only mode, and if that is true, set it to Record mode.