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Hundreds have posted, but I find no answers for Macs. Sometimes Messages refuses to send a photo:
Cannot Send Message
MMS Messaging needs to be enabled to
send this message.
How? I see nothing in Messages>Preferences. I can't find anything in (Apple)>Preferences
Mac Pro
I have an iPhone. I regularly send and receive texts and images from this MacPro. The people I exchange messages with are both iPhone users and users of other brands of pocket computers.
Today Messages put up the message shown above.
I do not find anything in System or Message preferences about enabling MMS messaging.
What is it this macOS application wants me to do. How do I do that?
The link discusses at length how to set up forwarding of messages from my iPhone to my Mac.
My question is about an error message my Mac when attempting to send a message from my Mac.
(My question is not about forwarding messages from my iPhone to my Mac. I am not having any trouble with that. Still, I did, on the Mac, go to Messages>Preferences>iMessage. Both my Apple ID and my iPhone phone number are checked. I also, on the iPhone, went to Settings>Messages> Text Message Forwarding. My Mac shows there and the switch is on, green. I'm not surprised by either of these facts.)
I have an iPhone. I regularly send and receive texts and images from this MacPro. The people I exchange messages with are both iPhone users and users of other brands of pocket computers.
Today Messages put up the message shown above.
I do not find anything in System or Message preferences about enabling MMS messaging.
What is it this macOS application wants me to do. How do I do that?
The link discusses at length how to set up forwarding of messages from my iPhone to my Mac.
My question is about an error message my Mac when attempting to send a message from my Mac.
(My question is not about forwarding messages from my iPhone to my Mac. I am not having any trouble with that. Still, I did, on the Mac, go to Messages>Preferences>iMessage. Both my Apple ID and my iPhone phone number are checked. I also, on the iPhone, went to Settings>Messages> Text Message Forwarding. My Mac shows there and the switch is on, green. I'm not surprised by either of these facts.)
Yes, I did understand that you are trying to send a MMS message using the Messages app on your Mac. The support article, I sent you, was the only one I could find from Apple.
Regardless, I send both SMS & MMS messages from my Macs, using the Messages app via my iPhone. I only have to configure the phone for two things to allow this to work:
SMS/MMS Forwarding Requirements
SMS and MMS messaging requires an activated carrier plan on any iPhone using iOS 8.1 or later. You can then send and receive SMS and MMS messages from these devices:
In order to send SMS/MMS messages with the Messages app on your Mac, you need to have an iPhone.
Ref: Forward SMS/MMS text messages from your iPhone to your Mac or iPad - Apple Support
macOS Messages how to enable MMS Messaging (Big Sur)
