Outbound Email IP used by Service@teamviwer.com

I have Geolocation blocking on my Watchguard Firewall.  I have exceptions set up for teamviewer to work with my firewall, however, I am no longer receiving emails from Teamviewer as you have recently changed your outbound email sending IP address and it is located outside my approved geolocation settings.

  While I have updated my Next Generation firewall to include your current IP list, I am unable to determine your sending email IP/domain.

 Specifically, I need the sending IP address/domain for the Activation emails that get sent to new users. ( i.e service@teamviewer.com)

Please advise