Why is the dial tone not working on my iPhone?

Cell phones don’t have dial tones… That’s a relic of landline phones.

Please explain what’s wrong.

Hello~ Not sure what you mean by “no dial tone”? If you can’t make calls…

If your call fails or you can’t receive calls on your iPhone - Apple Support

Maybe a forced restart would help…

Force restart iPhone - Apple Support

~Katana-San~