Screech when playing beep.ulaw over SIP trunk

I have a new install of Asterisk 13.6 and have everything working. The one problem I have is when a call rolls to voicemail and it plays the beep.ulaw file, the calling party hear’s a loud screech until he hangs up. I confirmed it was the beep file by writing a new extension that plays “hello world”’, then “beep”.
I notice that this doesn’t happen when using the same extensions and files from a local extension.
It seems to me that it could be my SIP provider Vitality, but I’m at a loss why?