stock message app

[monkeycsk]

is there a way to block SMS that are NOT in your contact??

 

[SpookDroid]

While there is an option to block unknown numbers in the Call settings section of your phone's Settings, not sure this would apply the rule to messaging. You can, however, block the texting number once you receive a text.

 

[Katrina White1]

I'm not on my S24U at the moment, but I think there's a DND setting that allows calls and texts from contacts only.

Edit for clarity: the DND setting is in your phone's notifications, not in the messaging app.