Managing sound and video settings during Teams meetings and calls for optimal communication
Hello TravisCoon,
Generally once we correctly set up the dial-in numbers for the user, it will be automatically added to the meeting invitations that are sent to meeting attendees. So for set up, we recommend you to double verify that you had follow the same steps as mention in Set up Audio Conferencing for Microsoft Teams.
Further if we have just set up audio conferencing, it should be possible that take time for sync up, so in this situation, we suggest you to wait for couple of hours and then check the result. Also check if you create Teams meeting from Teams app and Outlook app, call in number is viewed or not.
If configure has no issue and call in number not viewed from Teams and Outlook side, please go to Teams admin center > Users page to Reset conference ID and check if it helps.
Thanks and regards,
Ankita Vaidya