You receive a call or voicemail claiming to be from Apple support notifying you of suspicious activity with your Apple iCloud ID. The computer-generated recording’s goal is to snare you into giving up your iCloud ID and password as part of a new phishing campaign.
The call comes from a random or unknown number and if you don't pick up you’ll get a voicemail phishing for your iCloud ID and password:
“Hi, I am Jennifer, and I am calling you from online support Apple. This is to inform you that we have noticed some suspicious activity with your iCloud ID. We have been getting the notification on our main server the past few days. We seriously recommend you call (phone number given). I repeat (phone number). We request you not to use your computer or other Mac devices before speaking to our certified technicians. For help and support please call us.”
This is a clear attempt to scare you into calling the number back and giving up your Apple iCloud credentials.
There's no way Apple support will ever contact a customer using a computer-generated voice nor will they ever ask for your iCloud credentials.