How do I troubleshoot a phone that is not receiving texts from a certain contact?

1. Check that cellular data or Wi-Fi is enabled and the phone is connected to the internet
2. Check the signal strength of the phone
3. Check for any possible service outages in the area
4. Try restarting the phone and the messages app
5. Check the contact's settings and make sure they have the correct phone number
6. Make sure that the contact is not blocked or has been unsubscribed from a text thread