OS 10.10.5 Messages does not retrieve "To:" name from Contacts
Starting Messages and entering Contacts name shows "No Recipients" - typed 'Name' has pink background until clicked, then turns red. Sent message has green (SMS?) background for iPhone recipients [have iPhone]. 'Sent' Message was "Not Delivered". This is true on two Macs OS X 10.10.5 I have connected to same router.
All is well with my iPhone 6S (same network as above) Messaging - sent same message to same people [from Contacts] and sent/received OK as iMessage.