The way you've worded this it's hard to tell what's going on. I'm assuming your device is sending this message to people who text you, but your post almost sounds like you're getting this from someone. This is often a feature of do not disturb and/or would be a feature of your SMS app, in which case you would have to look thru its settings to figure out how to turn it off. Which app are you using, maybe someone can give you step by step on it? Is DND on for your device or is your notification volume set at zero, this could be triggering DND?
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