UPDATE August 10, 2018: New instructions can be found here
First, connect the domain you own in Obior:
In the menu, click Settings, and then click Domain Settings.
Click the Connect a Domain Your Own button.
Fill in your domain name and click SAVE at the bottom of the page.
Log in to Wix and go to Manage Domain.
Click on Advanced
Click on Edit DNS
Remove the CNAME m.yourdomain.com
That's it. You'll have to wait for a little while (usually less than an hour, but it might take up to 24 hours). If you still have any questions, email email@example.com.