Message Lamp not lighting on 2 out of 6 phones... (all phones on same board) KXTD 816 system, KXT-7431 phone, TVS50 VM. Can this be set from the phones? (please be specific) browsed manual and did not see anything definitive.
Thanks,
Dave

Mailbox COS in TVS 50, MW activation.

Also check call blocking in mailbox for some reason this disables the MW light.