Calls go straight to voicemail

This is almost always a setting left on by accident.

Steps

1. Check whether Do Not Disturb is on.Look for a DND icon on screen.
2. Check whether call forwarding is on.
3. In your phone system app, check your status isn't Away or Do Not Disturb.
4. Check the phone shows as registered (no warning icon).
5. Still happening?Ask your administrator to check your ring settings.