iPhone 11 Pro Max has sent 6 calls from the same number (work) straight to voicemail. It did not show up as a missed call and is not on the call log. They could not leave a voicemail because it said it was full even though it was not.
Do not disturb was not on, The phone did have service (one of the times was during a different call). No issues with this phone before this for the last two years.
Any idea on what is going on?