Authorize.Net issued an email to all developers of a change to improve reliability and performance. The change only affects users of Dynamics AX2009 using the Authorize.Net credit card interface. Authorize.Net recommends the change now, it will become automatic in June 2016. Please read the complete details of the Authorize.Net notice below:
To change your settings, modify the URL on the Credit Card Processors form to the new settings listed in their notice in the section entitled “Updating your solution”.
The old setting was https://secure.authorize.net/gateway/transact.dll.
The new setting would be https://secure2.authorize.net/gateway/transact.dll.
Note that, according to Authorize.Net’s notice, you can make the change immediately. We recommend that you make the change soon and test the new URL, since Authorize.Net suggests that the new service can have issues with firewall and IP address configurations. The old URL will switch to using the new service in June 2016. Making the change now, before it is automatic, could avoid a service disruption