When a user is trying to click the UI Action "Send SMS", there is a console error 'conferenceCancelCallback is not defined'
There are two ui actions that are meant to be working in conjunction with each other.
"Start Conference Call"
Both of them have a condition that ends in a role
Send SMS script has a function which is defined in start Conference Call. Without both UI actions on the record, they will not run properly.
Ensure that both conditions are on the users that need to use either or change the condition to fit the roles that your business case needs. As long as both ui actions are shown on the form at teh same time they will not have errors.