I got a new cell phone recently. As the world stood in line to pick up the latest iPhone 8, I graduated to the 6S. I pride myself on that actually. As with all new phones in the 21st century, the voicemail must be set up anew. I used the default message for the first few days, but finally settled down to record a more personal greeting.
If a phone rings once and then goes to voicemail or rings only briefly, it You can't definitively know the cause of a phone barely ringing and going to voicemail because neither a phone company nor the phone's operating system provider will tell you if your phone number is blocked.

4. "Hello, you've reached [your name and title]. I'm currently out on parental leave until [date]. In the meantime, please direct all phone calls to [alternate contact name] at [phone number] and emails to [email address]. Thanks, and I'll see you in [month you'll be back in the office]."
3. Setting Up an AT&T Visual Voicemail: Open your iPhone's Phone app. It's the white phone icon on a green background on the Home screen. Tap "Voicemail". It's in the bottom right corner of the screen.