The main URL for your account is the only verified URL for form submits by default. ActiveDEMAND will, as a security 'feature' throw away all data from any domain other than those set as authorized.
If you need another URL added to the list of authorized domains, if you have the proper permissions in your login account, you can add a verified URL to your account. Browse to your account settings (Administration->Account Settings), scroll down to Account Setup and make sure that tab is open, then scroll down to Authorized URLs, add a new URL. If you do not have permissions, please talk to your account administrator.
Note: Only administrators for agency partner accounts or Corporate Marketer accounts can authorize URLs. If you do not have access, please reach out to support to edit the list.