IPhone trying to send message as iMessage to non-iOS recipient

Question

When I create a new message, I select the contact (who has a non-iOS device, in this case a Samsung Galaxy), the contacts name is green, which is fine.
When I select the green contact's mobile number, the banner at the top goes from "New Message" to "New iMessage", the name stays green, but after typing a message the "Send" button remains greyed out so I cannot send it.
I don't know why the iPhone is trying to send this as an iMessage when it clearly knows full well that the recipient is non-iOS (as the contact name is green).
I have an iPhone 4s on iOS 7.1

Answer 1

Hey there Barkster,
It sounds like you are unable to send messages to a non iOS device when creating a new message. I would use the following troubleshooting from the following article:
iOS: Troubleshooting Messages
http://support.apple.com/kb/ts2755
To resolve issues sending and receiving SMS, follow these steps
Go to Settings and turn airplane mode off.
Make sure that you have a cellular network signal in the status bar of your iPhone. If there's no signal, learn more about troubleshooting no service.
Restart your iPhone.
Tap Settings > General > Reset > Reset Network Settings on your iPhone.
Remove your SIM card and insert it again.
If you still can't send or receive SMS, follow these steps
Make sure that the contact who's trying to message you isn't blocked in Settings > Messages > Blocked.
Make sure that you're using the area code with the contact's phone number. When sending messages internationally, you also need to use the contact's international code.
If you're using a "Pay as you go" SMS plan, make sure it has enough available balance. Contact your carrier if you're unsure of your SMS plan or the available balance.
If the issue occurs with a specific contact or contacts, back up or forward important messages and delete your current messaging threads with the contact. Create a new message to the contact and try again.
If the issue occurs with a specific contact or contacts, delete and recreate the contact from the Contacts app. Send a new message to the contact.
Back up and restore your iPhone as new.
If your carrier has recently ported your phone number, the porting process might not be complete. Contact your carrier to confirm that the porting process is complete.
Contact your carrier to confirm that you're provisioned for sending SMS and are in an area with cellular coverage.
Contact your carrier to verify there are no blocks or filters placed on your wireless account preventing you from sending SMS.
Thank you for using Apple Support Communities.
Take care,
Sterling