Sometimes (but infrequently) it is necessary to renew the Transaction Key provided to you by Authorize.net or Guardian Financial Services. ISN must be updated whenever a new Transaction Key is created. To generate a new Transaction Key and add it to ISN:
2). Click on "Account":
3). Click on "API Login ID and Transaction Key":
4). Enter the answer for your secret question and check "Disable Old Transaction Key(s)", then click Submit:
5). On the next screen your new Transaction Key will be available. Select it with your mouse, right click and click Copy.
6). In another browser tab, access your ISN website. When you are logged into the ISN, navigate to (main menu) --> Settings --> Office Settings, then under "My Office Settings" click on "My Payment Options."
7). In the Authorize.net or Guardian Financial Services part of this screen paste your Transaction Key:
Important: Once this is done, scroll down to and click on the "Save Payment Preferences" button.
All done! Now your ISN will be able to submit credit card payments through your Authorize.net or Guardian Financial Services accounts.