Execute JavaScript Trigger Opening Google and not Outlook

Hi there,
I am using the Execute JavaScript trigger to open and populate an email when the learner clicks a button. Our corporate standard email is Outlook. Several people on my team have helped me test the course on AO, SkillPort and on RegU. The trigger has worked all the time except once. One tester indicated that the trigger launched Google and not Outlook.
I'm not as technical as I'd like to be. Why would the trigger open Google and not the standard Outlook? Or a better questions: what can I do in the course to ensure that Outlook is launched by the trigger.
Here's a copy of the JS in the trigger.
------------------------------------------------------------
var player = GetPlayer();
var useremail = player.GetVar("EmailAddress");
var subject='Notes From Gateway to the CX Mindset Course';
var test1=player.GetVar('P1notes');
var test2=player.GetVar('P2notes');
var test3=player.GetVar('P3notes');
var test4=player.GetVar('P4notes');
var test5=player.GetVar('P5notes');
var test6=player.GetVar('P6notes');
var test7=player.GetVar('FAfinal');
var emailBody = 'Pillar 1:' + '\n' + test1 + '\n' + 'Pillar 2:' + '\n' + test2 + '\n' + 'Pillar 3' + '\n' + test3 + '\n' + 'Pillar 4' + '\n' + test4 + '\n' + 'Pillar 5' + '\n' + test5 + '\n' + 'Pillar 6' + '\n' + test6 + '\n'+ 'My Commitment' + '\n' + test7 + '\n';
window.location.href='mailto:'+useremail+'?subject='+subject+'&body='+encodeURIComponent(emailBody);
---------------------------------------------------------------
Thanks for your help!
Lisa