My Iphone 13

Good afternoon

I have an Iphone 13 which isn't even a year old since I'd pruchased it (I didn't purchased this from apple). When I go to send text messages its comes up failed to send (not delivered) but acutally it has delivered as the person has recived it. My Iphone is up to date with the latest software (IOS 16.3.1). This is a problem with the software i.e of sending text messages.

Thank you for your time reading this.