Yes, I'm using default metric Visits.
I've looked all reports, and I've found that there is no referrers data about mobile URL.
I think this is the real problem
We're using two domain names.
For desktop, (www.~~)/ For mobile, (m.~~)
However, I can't find the referrers data about mobile URL(m.~~)
This is the full screen captured image of our referrers reports.

Why has the problem like this occurred?
Is there a possibility that I made any mistakes?