My phone is blocking calls that I have not blocked. It rings once and then goes to voice mail. How can I fix this

Please check the following.

• Check your DND status - Settings > Focus [Do Not Disturb]; Use Focus on your iPhone, iPad, or iPod touch - Apple Support
• Check BedTime Status - Clock App; Use Bedtime to track your sleep on your iPhone - Apple Support
• Check your iPhone Sound Volume; Adjust the volume on your iPhone - Apple Support
• Check the device's Ringer switch; If you hear no sound or distorted sound from your iPhone, iPad, or ...
• Check Call Audio Routing; Call Audio Routing Bluetooth / Speaker / Automatic
• Check Auto Answer Calls; Turn off Auto Answer Calls
• Check the list of Blocked Numbers --> Block phone numbers, contacts, and emails on your iPhone ...

Hello Pusbuster, 

Welcome to the Apple Support Communities. 

Are you noticing any similar issues when you try to make an outbound call? If so, please start here: If you can't make or receive calls on your iPhone. 

The Apple Support article above explains how to troubleshoot cellular call issues. You’ll want to update your iOS software and carrier settings, check your network and iPhone settings, or contact your carrier for more support. 

All the best!