Follow these instructions to set up a custom domain.
Step 1: Create a CNAME record pointing from your domains (i.e. [SUBDOMAIN].[YOURDOMAIN].com, like preferences.domain.com) to customers.pushplanet.com
Step 2: Create a TXT record pointing awverify.[SUBDOMAIN].[YOUR-DOMAIN].com to pushplanet.azurewebsites.net
Step 3: Email us so we can verify and apply a SSL on our end (we will take care of this on our end).