I don't know if anyone can help me but I've got my default message type set to chat and the if chat isn't delivered type set to text message or multimedia message. Every time I send a message now it aways sends it as a text message. So do I keep it set at always ask if chat isn't delivered instead of resend as text message or multimedia message?
Do you send chat messages when not connected to the internet, either via a WiFi or a mobile data connection? Chat in Samsung Messages uses a similar system to iMessage on iOS, in which a message will default to SMS or MMS when not connected to the internet, again via WiFi or mobile data.
Also, Chat, as with iMessage, only works with devices in the same ecosystem (Samsung for Chat, Apple for iOS), so are the devices you're sending the messages to Samsung devices? Cause unfortunately Chat doesn't work across all Android devices, and DEFINITELY NOT WITH APPLE DEVICES.