2015 installed on my PC, now on my MacBook Pro...help with authorization

Help please,
I have a licensed version of 2015 on my PC desktop machine. I am attempting to install 2015 on my MacBook Pro; I have the license from the installed version, but they also ask for an authorization. Anyone know how to get that? Emails from Trimble confirming my original purchase do not mention the authorization number.

Resend License
SketchUp Pro Customer Service

I dug thru my old emails and finally found the original authorization.
Thanks for the quick response and info