I don't think this is anything to do with AX.
You can try the following steps to resolve this issue :
Go to start and type “services.msc”.
Hit Enter.
Go down to “Telephony” and double click.
Disable it, click apply, and click close.
Restart your system.
This will do the trick.
Although you will have to do it for each system on which the user is facing this issue.
Hope this helps!