One Tap host passcode

[vivianwi]

I schedule meetings for someone else & am his delegate.  He's asked for audio only meetings so tried doing One Tap Mobile.  However when he dials into the meeting he gets the message that the host passcode is incorrect.  Participants hear that the meeting has not yet started.  I've triple confirmed the passcode is the same as in the meeting invite.  This works for me when I send from my own account, but not as his delegate.  Wondering how to get the host passcode for his meetings to work.