I had the same problem.
Solved it by terminating the process "iTunesHelper" via 'Activity Monitor' and then removing the same process from the login dock
Link: Use Activity Monitor on your Mac - Apple Support
Two steps:
Step One:
Go to "Finder"
Click "Applications" on the left sidebar
Scroll to "Utilities" and double click
Sort processes by name by clicking the header bar
Find "iTunesHelper"
Click to highlight
Request to terminate/remove
Click ok
Step Two:
Make sure you're logged in to the admin account for the computer
Open "System Preferences" icon menu
Click "Users and Groups"
Click on the "Login Items" (It's a radio button tab next to the "password" option)
Highlight "iTuneshelper" to select it. DO NOT CLICK THE CHECKBOX TO HIDE THE PROCESS
Once process is highlighted, select the minus symbol " -- " (it's the one next to the plus "+" symbol, below the checkboxes that you shouldn't click)
On some machines, a pop up box will appear and ask you if you really want to terminate this process.
Click ok to terminate.
Problem solved. No more conference calls will be interrupted!