Hello!
I have a couple of suggestions.
- Make sure your "Do not disturb" mode is on, if it is then check if you have some kind of schedule for it and turn it off.
- Is your sim-card old? Some old sim cards can create issues and most service providers offer to update them.
- How long has this been an issue? Might want to check with the service provider if there are any issues with their network and the signal in your area.
Let me know if any of these fixes work for you.