Question: Why all credit card transactions made through HC panel are being declined by Authorize.net?
The most common reason of declined transactions is "Misconfiguration".
1. Do not change default values of General Merchant Settings in your Authorize.Net control panel
Follow the guidelines below for successful Authorize.Net integration in Hosting Controller.
2. If you wish to enable referrer security, then the following settings are supported by HC.
URL : http://secure.anydomain.com (example)
V.B. : Enable
V.L. : Enable
D.L. : Disable
R.D. : Disable
S.D. : Disable
If you are not using referrer security settings, then remove all URL's from V.B and V.L sections.
Note: All credit card transactions made through HC panel are only processed in "Authorized Mode". Merchants should review and capture transactions through Authorize.net web interface.