I figured someone here might have experience with this and know what to do:

We are using Marketo to email customers and link them to our websites. Marketo requires a unique subdomain (“CNAME”) for email tracking links that is distinct from any of our actual subdomains. For example, our Marketo landing pages are on “go.oursite.com,” and the Marketo email links use “info.oursite.com.” Note that there is no actual content on the “info” subdomain -- it only appears in these email links.

We have UTM codes on all of these links, but they’re not currently being picked up by Amplitude at all. It seems that because “go” and “info” both look like they’re both subdomains of “oursite.com”, Amplitude is suppressing all attribution information from these email links. We also link to other subdomains and are seeing the same issue on those, including our main “www.oursite.com” domain. 

If it makes a difference: we’re using Google Tag Manager for our implementation, with the Amplitude tag template. 

So, for those of you using both Marketo and Amplitude, how do you handle attribution tracking with UTMs so you’re not running into this problem?