First of all, welcome to iMore. In regards to your question, I have a question. Have you tried doing a forced restart on your iPhone? It's a troubleshooting method that often fixes little problems.
To do a "forced restart on your iPhone 7, hold down both the Volume Down button on the left side of the device and the Sleep/Wake button on the right side of the device at the same time. Hold them down for approximately 10 seconds until the screen goes dark and the Apple logo appears. At this point, you can release both buttons, because your phone is restarting.
Give this a try and see if this fixes the issue. Please let us know!