Good day! I would just like to ask if there is any problem with the software if I cannot send multiple recipients with SMS messaging? My iOS is up to date, 11.4.1. Need answers please. Thank you.

You can't turn SMS on or off from your phone. There are no settings that do that. You need to contact your carrier to do that.

Messages>Send as SMS does not turn SMS on or off. It simply changes the phone's default action if an iMessage fails.

Have you gone to Settings>Messages>MMS Messaging and made sure that it's turned on? If you don't see that feature, contact your carrier.

If the problem is something else, please explain.

That is not the cause of your problem. They mean the same thing. It just depends on what county you're in.

I’m having this problem too. MMS is on, as is Group Messaging. Does SMS need to be turned on?